Merged r12419.
Merged r12420 (#15684).
Merged r12415 (#15677).
Merged r12414 (#15623).
Merged r12349 (#15523).
Merged r12309 (#15398).
make WatchersHelperTest passes when config.threadsafe! is enabled (#12097)
make IssuesHelperTest passes when config.threadsafe! is enabled (#12097)
use environment variable for extacting SCM repositories in ci.rake
Merged r12424 from trunk to 2.4-stable.
fix svn raw diff failure on svn version 1.6.17 (revision 1128011).