Bug Fix: Allow longer source URLs for redirect module

## Ready State: Yes

The redirect module limits source URL lengths to 255 characters. This patch changes the database field from varchar(255) to a medium text field.

## Requirements & Dependencies

* None.

## Deployment Instructions

* Merge code.

## Usage/Test Instructions

* Applying the patch to a site where the redirect module is installed and enabled, run update.php and the the source field in the redirect database table should be a text field rather than varchar.
* Applying the patch to a site where redirect is not installed, the redirect module should create the proper database structure when installed.