rebase: deprecate --rebase-merges=""
The unusual syntax --rebase-merges="" (that is, --rebase-merges with an
empty string argument) has been an undocumented synonym of
--rebase-merges without an argument. Deprecate that syntax to avoid
confusion when a rebase.rebaseMerges config option is introduced, where
rebase.rebaseMerges="" will be equivalent to --no-rebase-merges.
It is not likely that anyone is actually using this syntax, but just in
case, deprecate the empty string argument instead of dropping support
for it immediately.
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>