Fix bash conditional error when current_oc_version is empty

Ensure current_oc_version is properly quoted in the if statement
to prevent "unary operator expected" error when the variable is unset.

build-patched-kao-kcmo-images.sh

@@ -74,7 +74,7 @@ if [ -f "$OC" ]; then
 	current_oc_version=$(${OC} version --client -o json |jq -r .releaseClientVersion)
 fi
 echo "OC version: ${current_oc_version-}"
-if [ ${current_oc_version-} = ${OPENSHIFT_RELEASE_VERSION} ]; then
+if [ "${current_oc_version-}" = "${OPENSHIFT_RELEASE_VERSION}" ]; then
     echo "No need to download oc, local oc is already version ${OPENSHIFT_RELEASE_VERSION}"
 else
     curl -L "${MIRROR}/${OPENSHIFT_RELEASE_VERSION}/openshift-client-linux-${OPENSHIFT_RELEASE_VERSION}.tar.gz" | tar -zx -C openshift-clients/linux oc