Previously, a backup bundle could overwrite an existing bundle and cause user
data loss. For instance, if you have A<-B<-C and strip B, it produces backup
bundle B-backup.hg. If you then hg pull -r B B-backup.hg and strip it again, it
overwrites the existing B-backup.hg and C is lost.
The fix is to add a hash of all the nodes inside that bundle to the filename.
Fixed up existing tests and added a new test in test-strip.t
Show status messages while rebasing, similar to what graft do:
rebasing 12:2647734878ef "fork" (tip)
This gives more context for the user when resolving conflicts.
Globbing the hash made it harder to maintain tests with run-tests -i when it
was so far by the generated test output.
The hashes are stable and we just need to add a (glob).
Many tests didn't change back from subdirectories at the end of the tests ...
and they don't have to. The missing 'cd ..' could always be added when another
test case is added to the test file.
This change do that tests (99.5%) consistently end up in $TESTDIR where they
started, thus making it simpler to extend them or move them around.
