Unresolved resource dependencies when using Fn::ImportValue for role in function with kinesis event handler
# This is a Bug Report

## Description

When I have a AWS service with a function that defines both a kinesis stream endpoint and a role  a cloudformation import (using Fn::ImportValue) I receive the following error:

```
The CloudFormation template is invalid: Template format error: Unresolved resource dependencies [IamRoleLambdaExecution] in the Resources block of the template
```

My Function Role is defined using:
```
role: 
   Fn::ImportValue: Dev-Shared-Lambda-Resources-ExtendedLambdaRoleArn
```

In the generated template I can see that a dependency to the default role has been generated for the Kinesis mapping:

```    "PostingsEventSourceMappingKinesisDevSharedKinesisResourcesPostingsKinesisStreamArn": {
      "Type": "AWS::Lambda::EventSourceMapping",
      "DependsOn": "IamRoleLambdaExecution"
}
```

The issue appears to be the code in: `/Users/toby.hede/src/serverless/lib/plugins/aws/package/compile/events/stream/index.js`
at around line 125.

I should be able to use the `Fn::ImportValue` function to reference a role when using a kinesis event handler. 

We have a group of  resources that a couple of services share, and imports are useful for managing these dependencies.

I have another service using a role via `Fn::ImportValue` that does not have a kinesis stream and this works ok. The bad dependency is just in the event mapping for kinesis.

## Additional Data

* ***Serverless Framework Version you're using***: 1.19.0 and master
* ***Operating System***: OSX
* ***Stack Trace***:
```
➜  service-postings git:(master) ✗ SLS_DEBUG=true AWS_PROFILE=r1-dev sls deploy --stage th --kinesis-env dev
Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Configurating CloudWatch log retention
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Validating template...

  Error --------------------------------------------------

  The CloudFormation template is invalid: Template format error: Unresolved resource dependencies [IamRoleLambdaExecution] in the Resources block of the template

     For debugging logs, run again after setting the "SLS_DEBUG=*" environment variable.

  Stack Trace --------------------------------------------

Error: The CloudFormation template is invalid: Template format error: Unresolved resource dependencies [IamRoleLambdaExecution] in the Resources block of the template
    at provider.request.catch (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/lib/validateTemplate.js:25:13)
From previous event:
    at AwsDeploy.validateTemplate (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/lib/validateTemplate.js:20:12)
From previous event:
    at AwsDeploy.BbPromise.bind.then (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:117:39)
From previous event:
    at Object.aws:deploy:deploy:validateTemplate [as hook] (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:113:10)
    at BbPromise.reduce (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:236:55)
From previous event:
    at PluginManager.invoke (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:236:22)
    at PluginManager.spawn (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:248:17)
    at AwsDeploy.BbPromise.bind.then (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:91:48)
From previous event:
    at Object.deploy:deploy [as hook] (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:87:10)
    at BbPromise.reduce (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:236:55)
From previous event:
    at PluginManager.invoke (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:236:22)
    at PluginManager.run (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:255:17)
    at variables.populateService.then (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/Serverless.js:99:33)
    at runCallback (timers.js:672:20)
    at tryOnImmediate (timers.js:645:5)
    at processImmediate [as _immediateCallback] (timers.js:617:5)
From previous event:
    at Serverless.run (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/Serverless.js:86:74)
    at serverless.init.then (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/bin/serverless:39:50)
```

My function is defined using the following serverless.yml declaration:

```
  postings:
    handler: postings/handler.main
    role:
      Fn::ImportValue: Dev-Shared-Lambda-Resources-ExtendedLambdaRoleArn
    events:
      - stream:
          type: kinesis
          arn:
            Fn::ImportValue: Dev-Shared-Kinesis-Resources-PostingsKinesisStreamArn
```
Unresolved resource dependencies when using Fn::ImportValue for role in function with kinesis event handler
# This is a Bug Report

## Description

When I have a AWS service with a function that defines both a kinesis stream endpoint and a role  a cloudformation import (using Fn::ImportValue) I receive the following error:

```
The CloudFormation template is invalid: Template format error: Unresolved resource dependencies [IamRoleLambdaExecution] in the Resources block of the template
```

My Function Role is defined using:
```
role: 
   Fn::ImportValue: Dev-Shared-Lambda-Resources-ExtendedLambdaRoleArn
```

In the generated template I can see that a dependency to the default role has been generated for the Kinesis mapping:

```    "PostingsEventSourceMappingKinesisDevSharedKinesisResourcesPostingsKinesisStreamArn": {
      "Type": "AWS::Lambda::EventSourceMapping",
      "DependsOn": "IamRoleLambdaExecution"
}
```

The issue appears to be the code in: `/Users/toby.hede/src/serverless/lib/plugins/aws/package/compile/events/stream/index.js`
at around line 125.

I should be able to use the `Fn::ImportValue` function to reference a role when using a kinesis event handler. 

We have a group of  resources that a couple of services share, and imports are useful for managing these dependencies.

I have another service using a role via `Fn::ImportValue` that does not have a kinesis stream and this works ok. The bad dependency is just in the event mapping for kinesis.

## Additional Data

* ***Serverless Framework Version you're using***: 1.19.0 and master
* ***Operating System***: OSX
* ***Stack Trace***:
```
➜  service-postings git:(master) ✗ SLS_DEBUG=true AWS_PROFILE=r1-dev sls deploy --stage th --kinesis-env dev
Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Configurating CloudWatch log retention
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Validating template...

  Error --------------------------------------------------

  The CloudFormation template is invalid: Template format error: Unresolved resource dependencies [IamRoleLambdaExecution] in the Resources block of the template

     For debugging logs, run again after setting the "SLS_DEBUG=*" environment variable.

  Stack Trace --------------------------------------------

Error: The CloudFormation template is invalid: Template format error: Unresolved resource dependencies [IamRoleLambdaExecution] in the Resources block of the template
    at provider.request.catch (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/lib/validateTemplate.js:25:13)
From previous event:
    at AwsDeploy.validateTemplate (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/lib/validateTemplate.js:20:12)
From previous event:
    at AwsDeploy.BbPromise.bind.then (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:117:39)
From previous event:
    at Object.aws:deploy:deploy:validateTemplate [as hook] (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:113:10)
    at BbPromise.reduce (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:236:55)
From previous event:
    at PluginManager.invoke (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:236:22)
    at PluginManager.spawn (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:248:17)
    at AwsDeploy.BbPromise.bind.then (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:91:48)
From previous event:
    at Object.deploy:deploy [as hook] (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:87:10)
    at BbPromise.reduce (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:236:55)
From previous event:
    at PluginManager.invoke (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:236:22)
    at PluginManager.run (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/classes/PluginManager.js:255:17)
    at variables.populateService.then (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/Serverless.js:99:33)
    at runCallback (timers.js:672:20)
    at tryOnImmediate (timers.js:645:5)
    at processImmediate [as _immediateCallback] (timers.js:617:5)
From previous event:
    at Serverless.run (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/lib/Serverless.js:86:74)
    at serverless.init.then (/Users/toby.hede/.nvm/versions/node/v7.10.0/lib/node_modules/serverless/bin/serverless:39:50)
```

My function is defined using the following serverless.yml declaration:

```
  postings:
    handler: postings/handler.main
    role:
      Fn::ImportValue: Dev-Shared-Lambda-Resources-ExtendedLambdaRoleArn
    events:
      - stream:
          type: kinesis
          arn:
            Fn::ImportValue: Dev-Shared-Kinesis-Resources-PostingsKinesisStreamArn
```