0.12.1dev: Correctly handle an empty `[trac] backup_dir` option.
0.12.1dev: Correctly handle an empty `[trac] backup_dir` option.

Closes #9556.


git-svn-id: 30ec3c1a2098df185a8733d0352d646269562639@9989 af82e41b-90c4-0310-8c96-b1721e28e2e2

dafrito/trac-mirror,exocad/exotrac,dafrito/trac-mirror,moreati/trac-gitsvn,exocad/exotrac,dafrito/trac-mirror,exocad/exotrac,exocad/exotrac,dafrito/trac-mirror,moreati/trac-gitsvn,moreati/trac-gitsvn,moreati/trac-gitsvn