ci: Fix release version check

The git tag are vX.Y.Z and the VERSION file is just X.Y.Z so need to
deal with the `v` in the check.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>

.buildkite/deploy.yml

@@ -9,7 +9,7 @@ steps:
 
       - >
         if [ -n "${BUILDKITE_TAG}" ]; then
-           if [ "${BUILDKITE_TAG}" != $${release} ]; then
+           if [ "${BUILDKITE_TAG}" != v"$${release}" ]; then
               echo "Need to fix VERSION file.  Tag ${BUILDKITE_TAG} doesn't match $${release}"
               exit 1
            fi