util: fix bug in tagbranch

After mulptiple edits of the script, there is a case when bash
variable is not properly quoted, let's fix it.

BRANCH=cr50
BUG=b:64698702
TEST=verified proper tag description set by git

Change-Id: I5847437cde717bb6e1f4b672fe6008b8e6e6f4e3
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/667917
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Shawn N <shawnn@chromium.org>

util/tagbranch.sh

@@ -67,7 +67,8 @@ TAG="v1.${TAG_BASE}.0"
 BASE_SHA="$(git rev-list --ancestry-path "${BRANCH_POINT}".."${UPSTREAM}" |
     tail -1)"
 
-if git tag -a -m 'firmware branch ${TAG}' "${TAG}" "${BASE_SHA}"; then
+echo "Will run git tag -a -m \"firmware branch ${TAG}\" ${TAG} ${BASE_SHA}"
+if git tag -a -m "firmware branch ${TAG}" "${TAG}" "${BASE_SHA}"; then
   cat <<EOF
 
 A new tag '$TAG' has been set. Use the following command