Further reduce memory usage during path_history queries (follow-up to r2151). 
Further reduce memory usage during path_history queries (follow-up to r2151). 

Thanks to exarkun for the report and bdash for hinting me to the fix.


git-svn-id: 0d96b0c1a6983ccc08b3732614f4d6bfcf9cbb42@2978 af82e41b-90c4-0310-8c96-b1721e28e2e2

rbaumg/trac,rbaumg/trac,rbaumg/trac,rbaumg/trac