handing the proxy_redirect nginx directive

**Creating the possibility of handing the proxy_redirect nginx directive to fix an annoying jenkins reverse proxy broken warning**

Here is the jenkins help page when you get this reverse proxy broken issue https://wiki.jenkins-ci.org/display/JENKINS/Jenkins+says+my+reverse+proxy+setup+is+broken

If you're running nginx as a reverse proxy ( with SSL ) in front of plain-text HTTP jenkins now you can configure nginx's reverse_proxy directive to fix the above warning from jenkins
Btw maybe another bug but I get this error on both versions of puppet I've tried
```ruby
Invalid parameter rewrite_rules at /vagrant/modules/nginx/manifests/resource/vhost.pp:427 on node jenkins.local
```
Tried it on these specs:
```
lsb_release -a
LSB Version:	:base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch
Distributor ID:	CentOS
Description:	CentOS release 6.4 (Final)
Release:	6.4
Codename:	Final
```
```
cat Modulefile

name    'jfryman-nginx'
version '0.0.7'
source 'http://github.com/jfryman/puppet-nginx'
author 'James Fryman'
license 'Apache License Version 2.0'
summary 'Puppet NGINX management module'
description 'This module can be used for basic NGINX Management'
project_page 'http://github.com/jfryman/puppet-nginx'

dependency 'puppetlabs/stdlib', '>= 0.1.6'
dependency 'puppetlabs/apt', '>= 1.0.0'
dependency 'puppetlabs/concat', '>= 1.0.0'
```
```
# puppet --version
2.7.25
```
or
```
# puppet --version
3.3.1
```
To get around it I've had to comment out line 426 of `vhost.pp`
```
<snip>
rewrite_rules       => $rewrite_rules,
<snip>
```