Interactive rebase - make selected commit available too

Since we select final commit for interactive rebase in a listed dialog,
it is IMO expected and more user-frendly to also have selected commit in
the interactive rebase list.

Change-Id: I56febd024cc174bcd046b1f02bccfe990043aae4
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>