git-p4: fix skipSubmitEdit regression

git-p4: fix skipSubmitEdit regression

Commit 7c766e5 (git-p4: introduce skipSubmitEdit, 2011-12-04)
made it easier to automate submission to p4, but broke the most
common case.

Add a test for when the user really does edit and save the change
template, and fix the bug that causes the test to fail.

Also add a confirmation message when submission is cancelled.

Reported-by: Michael Horowitz <michael.horowitz@ieee.org>
Signed-off-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>