git-p4: add RCS keyword status message

git-p4: add RCS keyword status message

During the p4 submit process, git-p4 will attempt to apply a patch
to the files found in the p4 workspace. However, if P4 uses RCS
keyword expansion, this patch may fail.

When the patch fails, the user is alerted to the failure and that git-p4
will attempt to clear the expanded text from the files and re-apply
the patch. The current version of git-p4 does not tell the user the
result of the re-apply attempt after the RCS expansion has been removed
which can be confusing.

Add a new print statement after the git patch has been successfully
applied when the RCS keywords have been cleansed.

Signed-off-by: Ben Keene <seraphire@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>