precheck: Improve rebase detection

REBASE_HEAD will sometimes be left behind in .git after an interactive
rebase concludes (if the last step completed was a squash or edit, for
instance).  Likewise, it may be missing _during_ a rebase, such as when
paused on a break command.

Instead, use the presence of the rebase-merge or rebase-apply
directories as the "rebase in progress" signal.  Note still that
rebase-apply will exist during git-am as well.

These two directories are utilized by the two rebase implementation
backends, so we shouldn't normally expect to see them both at the same
time.

Signed-off-by: Matt Hunter <m@lfurio.us>

0 files changed, 0 insertions, 0 deletions