Backport r1455352 onto 1.7.x:
Backport r1455352 onto 1.7.x:

 * r1455352
   Improve logic in mod_dav_svn's implementation of lock.
   Votes:
     +1: breser, philip, pburba



git-svn-id: f31f7a5323bbe4a1034a732b81b9abb714edbfbf@1462331 13f79535-47bb-0310-9956-ffa450edef68

wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion