This is caused by changes in SVN 1.7 relating to ignored files - they are no longer reported by default in 'svn status' (the SVNKit API used by Jenkins mirrors this behaviour).
In the workspace for a Jenkins project (after the job has run), no changes are shown:
[root@devemr01 UTIL_TRUNK]# svn status
However, the below command shows files/directories that are marked as ignored:
[root@devemr01 UTIL_TRUNK]# svn status --no-ignore
I .gradle
I build
...and creating a new file that isn't ignored shows up in 'svn status':
[root@devemr01 UTIL_TRUNK]# touch foo
[root@devemr01 UTIL_TRUNK]# svn status
? foo
UpdateWithCleanUpdater.java needs to explicitly request that SVNKit include 'ignored' files such that they can be deleted.
Subversion Plugin DOES NOT support 1.7.