Add godeps to revision lock cloudwatch library.

This change introduces `godep` to mark the dependencies on external libraries.

To install `godep`:

```
  go get github.com/kr/godep
```

To generate the initial Godeps file run:

```
  godep save -copy=false
```
This creates a dependency JSON file.  I edited the verison SHA's for two libraries:

  https://github.com/crowdmob/goamz/aws
  https://github.com/crowdmob/goamz/cloudwatch

I set the SHA to this version:

 [bfa553e3b7d6416a36cb81ff5f379acfb9b93f0d](https://github.com/crowdmob/goamz/commit/bfa553e3b7d6416a36cb81ff5f379acfb9b93f0d)

Using this SHA for the libaries, I was able to get the build to work with the following command:

  godep go build