Plugin activation hotfix

* In initial release migrations dir taken from wordpress dir rather than be hardcoded.
Locally all was ok as always, but not on your wordpresses :(
* Please upgrade, deactivate and active plugin.

git-svn-id: https://plugins.svn.wordpress.org/wp-testing/trunk@1003362 b8457f37-d9ea-0310-8a92-e5e31aec5664