Bugfix: LDC-458 - panels update to fix mini panel error message

## Ready State: Yes

Relates to:
https://imagex.atlassian.net/browse/LDC-458
https://drupal.org/node/1480366

Updates panels to dev version to fix mini panels error.

## Requirements & Dependencies

None

## Deployment Instructions

* Merge code.
* Clear caches with `drush cache-clear all`

## Usage/Test Instructions

* Run new build & install, ensure the error in the jira task (https://imagex.atlassian.net/browse/LDC-458) is no longer present.