Remove unused sh functions from git-mergetool.sh

The tidy up of git mergetool's backup files handling made the two shell functions save_backup and remove_backup redundant. This commit removes these now unused functions.

---

This patch belongs on top of the mergetool updates in pu. It removes a couple of shell functions which were made redundant in commit 6fef6e2... In fact it should logically be squashed into that commit.

 git-mergetool.sh |   12 ------------
 1 files changed, 0 insertions(+), 12 deletions(-)

index d12bedf..5c86f69 100755
@@ -127,18 +127,6 @@ check_unchanged () {
     fi
 }
 
-save_backup () {
-    if test "$status" -eq 0; then
-	mv -- "$BACKUP" "$MERGED.orig"
-    fi
-}
-
-remove_backup () {
-    if test "$status" -eq 0; then
-	rm "$BACKUP"
-    fi
-}

Will do. Thanks.