Switch rebase editor class to exec rebase so that it takes over the
console to allow the user to continue/skip/abort as they would
normally. Update the instruction set for rebase to re-call
git-upstream as a final step for user convenience to finish the import.
When the EDITOR or GIT_EDITOR is defined to change what editor is used
to edit the sequence of instructions to git-rebase, git will recall the
same editor in those variables if one of the instructions is 'reword',
'edit', or 'squash' in order to amend the commit message. Change the
rebaseeditor script to be able to handle being called with a
COMMIT_EDITMSG file when this occurs.
This allows the 'edit', 'reword', 'squash' & 'fixup' commands to git
rebase to function as expected by the user irrespective of whether a
conflict has been encountered first or not.
Still results in git rebase outputting additional information after
the import has completed, but avoids the main issue of the interactive
mode being unusable due to ignoring the result of the git-rebase call
unless it exits with an error, which only occurs for conflicts.
Change-Id: Ic125c85b868d816ef13fac6f503092ac3142b4de
Closes-Bug: #1402032
c195b69c6b