Applied rubocop changes to wp_wysija plugin

I applied the rubocop suggested fixes to the file, changed the check message to a verbose one and added some comments. To test, you need to reverse patch the downloaded plugin because the developers applied the fix to all previous versions on their corresponding tags :(
### Instructions
 - [x] Download `http://downloads.wordpress.org/plugin/wysija-newsletters.2.6.7.zip`
 - [x] install it
 - [x] save the following to your wp-content/plugins/ folder: `wysija.patch`
```
--- a/wysija-newsletters/helpers/back.php
+++ b/wysija-newsletters/helpers/back.php
@@ -179,7 +179,7 @@
      */
     function verify_capability(){
+        if( isset( $_REQUEST['page'] ) && substr( $_REQUEST['page'] ,0 ,7 ) == 'wysija_' ){
+
+            switch( $_REQUEST['page'] ){
-        if( isset( $_GET['page'] ) && substr( $_GET['page'] ,0 ,7 ) == 'wysija_' ){
-
-            switch( $_GET['page'] ){
                 case 'wysija_campaigns':
                     $role_needed = 'wysija_newsletters';
```
 - [ ] Apply it via `patch -p1 < wysija.patch`

And the exploit should work again.

### Output
![exploit](https://cloud.githubusercontent.com/assets/105281/3631654/49172c48-0eb9-11e4-9ccb-6920520e99d5.png)

### Rubocop Warnings generated
```
Inspecting 1 file
W

Offenses:

modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:1:1: C: Missing utf-8 encoding comment.
##
^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:16:7: C: Align the parameters of a method call if they span more than one line.
      'Name'           => 'Wordpress MailPoet Newsletters (wysija-newsletters) Unauthenticated File Upload',
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:37:12: C: Space inside square brackets detected.
          [ 'URL', 'http://blog.sucuri.net/2014/07/remote-file-upload-vulnerability-on-mailpoet-wysija-newsletters.html' ],
           ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:37:121: C: Space inside square brackets detected.
          [ 'URL', 'http://blog.sucuri.net/2014/07/remote-file-upload-vulnerability-on-mailpoet-wysija-newsletters.html' ],
                                                                                                                        ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:38:12: C: Space inside square brackets detected.
          [ 'URL', 'http://www.mailpoet.com/security-update-part-2/'],
           ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:39:12: C: Space inside square brackets detected.
          [ 'URL', 'https://plugins.trac.wordpress.org/changeset/943427/wysija-newsletters/trunk/helpers/back.php']
           ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:44:28: C: Space inside square brackets detected.
      'Targets'        => [ ['wysija-newsletters < 2.6.8', {}] ],
                           ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:44:63: C: Space inside square brackets detected.
      'Targets'        => [ ['wysija-newsletters < 2.6.8', {}] ],
                                                              ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:61:33: W: Shadowing outer local variable - content.
    content.each_pair do |name, content|
                                ^^^^^^^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:70:28: C: Redundant curly braces around a hash parameter.
    res = send_request_cgi({
                           ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:71:7: C: Use 2 spaces for indentation in a hash, relative to the first position after the preceding left parenthesis.
      'uri'    => readme_url,
      ^^^^^^^^^^^^^^^^^^^^^^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:73:5: C: Indent the right brace the same as the first position after the preceding left parenthesis.
    })
    ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:75:5: C: Favor modifier if usage when having a single-line body. Another good alternative is the usage of control flow &&/||.
    if res.nil? || res.code != 200
    ^^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:85:5: C: Favor modifier if usage when having a single-line body. Another good alternative is the usage of control flow &&/||.
    if version.nil?
    ^^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:117:28: C: Redundant curly braces around a hash parameter.
    res = send_request_cgi({
                           ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:118:7: C: Use 2 spaces for indentation in a hash, relative to the first position after the preceding left parenthesis.
      'method'   => 'POST',
      ^^^^^^^^^^^^^^^^^^^^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:123:5: C: Indent the right brace the same as the first position after the preceding left parenthesis.
    })
    ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:138:5: W: Useless assignment to variable - res.
    res = send_request_cgi({
    ^^^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:138:28: C: Redundant curly braces around a hash parameter.
    res = send_request_cgi({
                           ^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:139:7: C: Use 2 spaces for indentation in a hash, relative to the first position after the preceding left parenthesis.
      'uri'    => payload_uri,
      ^^^^^^^^^^^^^^^^^^^^^^^
modules/exploits/unix/webapp/wp_wysija_newsletters_upload.rb:141:5: C: Indent the right brace the same as the first position after the preceding left parenthesis.
    })
    ^

1 file inspected, 21 offenses detected
```