A bit more sanity checking of the 'svn up' output

git-svn-id: https://plugins.svn.wordpress.org/automatic-updater/trunk@751992 b8457f37-d9ea-0310-8a92-e5e31aec5664
Version: 0.9.1

git-svn-id: https://plugins.svn.wordpress.org/automatic-updater/trunk@751994 b8457f37-d9ea-0310-8a92-e5e31aec5664
Release: 0.9.1

git-svn-id: https://plugins.svn.wordpress.org/automatic-updater/trunk@751996 b8457f37-d9ea-0310-8a92-e5e31aec5664