util: fix bug in tagbranch
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 <5515d6d2d0829cbe0dd0dcf2094aaded06d58514@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/667917
Reviewed-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>
Reviewed-by: Shawn N <5259333ce42e3ace6a73988cec7115ed9d3a661a@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec