commit-msg: Do not add Change-Id to temp commits

Temporary commits that are created using "git commit --fixup"
or "git commit --squash" are not supposed to be pushed to gerrit.

Prevent pushing them by mistake, at least for project that
require Change-Id.

Change-Id: I9ac25b7384a128fea376a357f2b324b286622e2c

gerrit-server/src/main/resources/com/google/gerrit/server/tools/root/hooks/commit-msg

@@ -38,6 +38,12 @@ add_ChangeId() {
 		return
 	fi
 
+	# Do not add Change-Id to temp commits
+	if echo "$clean_message" | head -1 | grep -q '^\(fixup\|squash\)!'
+	then
+		return
+	fi
+
 	if test "false" = "`git config --bool --get gerrit.createChangeId`"
 	then
 		return