0.13dev: Preserves permissions and ownerships of old attachments directory for new attachments directory if possible
0.13dev: Preserves permissions and ownerships of old attachments directory for new attachments directory if possible

Part of #10313.


git-svn-id: 0d96b0c1a6983ccc08b3732614f4d6bfcf9cbb42@11040 af82e41b-90c4-0310-8c96-b1721e28e2e2

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