After doing a merge --squash, and commit afterwards, the commit message
template SQUASH_MSG in the git directory is not removed, which means that
the content of SQUASH_MSG is used as default commit message for all
subsequent commits. So have git commit remove the file SQUASH_MSG from
the git directory upon a successful commit.
The problem was discovered by Frédéric Brière, reported through
http://bugs.debian.org/464656
Signed-off-by: Gerrit Pape <pape@smarden.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>