bugfix: git-branch-rebaser support any default branch
bugfix: git-branch-rebaser support any default branch

The script currently supports only master. Other commands were updated
to support multiple default branches, update this one the same.

Signed-off-by: Tomer Arbel Eliyahu <b1429e76db16b5907079fac30288f68952a0f52a@intel.com>

unixorn/git-extra-commands,unixorn/git-extra-commands,unixorn/git-extra-commands,unixorn/git-extra-commands