rebase: fix --collapse with --keepbranches (
issue2100)
This was broken in
38fe86fb16e3.
test-convert-cvs: filter unstable cvs output.
The order choosen by cvs to display commit is not stable when the tests are run
under heavy CPU/IO load. This leads to irrelevant failures of the test suite.
This changeset filters four lines impacted by this instability. The result of
the conversion is still verified.