fix: release-catalog.sh (#1971)

Signed-off-by: Anatolii Bazko <abazko@redhat.com>

Author: tolusha

build/scripts/olm/release-catalog.sh

@@ -23,7 +23,6 @@ init() {
   unset CHANNEL
   unset CATALOG_IMAGE
   unset BUNDLE_IMAGE
-  unset IMAGE_TOOL
 
   while [[ "$#" -gt 0 ]]; do
     case $1 in