MultiRepos: fix repository timeline filters to correctly handle all the different situations  - single default repository; show only ''Repository checkins'' provider  - aliased default repository; show the alias  - non-aliased default repository; show ''(default)'' repository filter
MultiRepos: fix repository timeline filters to correctly handle all the different situations
 - single default repository; show only ''Repository checkins'' provider
 - aliased default repository; show the alias
 - non-aliased default repository; show ''(default)'' repository filter

Completes work on #8758.


git-svn-id: 724832444bcc56d647a9134c92586fee9d70f226@8780 af82e41b-90c4-0310-8c96-b1721e28e2e2

walty8/trac,netjunki/trac-Pygit2,walty8/trac,jun66j5/trac-ja,netjunki/trac-Pygit2,jun66j5/trac-ja,jun66j5/trac-ja,netjunki/trac-Pygit2,walty8/trac,jun66j5/trac-ja,walty8/trac