there is no clean up on svn:externals when they appear locked

https://support.atlassian.com/browse/BSP-2829

2010-04-07 13:51:47,280 ERROR [BAM::Default Agent::Agent:pool-4-thread-1] [BuildLoggerUpdateEventHandler] Update of external at 'C:\BT_Server\bamboo-home\xml-data\build-dir\ATLAS-ATLASSTANDALONENIGHTLY\Atlas' has been skipped: svn: Failed to load properties from disk
svn: Malformed file
svn: Can't read length line from file C:\BT_Server\bamboo-home\xml-data\build-dir\ATLAS-ATLASSTANDALONENIGHTLY\Atlas\Atlas.Maps\Imagens\MapaNivel2\.svn\all-wcprops: null

Subsequently the svn client locks the working copy.

/Users/ukuhnhardt/Downloads/atlassian-bamboo - Copy 2.log:40009: 2010-04-08 01:00:00,799 ERROR [BAM::Default Agent::Agent:pool-4-thread-1] [BuildLoggerUpdateEventHandler] Update of external at 'C:\BT_Server\bamboo-home\xml-data\build-dir\ATLAS-ATLASSTANDALONENIGHTLY\Atlas' failed because it is locked.