Pass kernel version to mosk base image

Related-Prod: PRODX-3456
Change-Id: I403e5deae2598cc06dd447a278152954357de1b6
diff --git a/mosk-images/build_image.sh b/mosk-images/build_image.sh
index 10450a8..571f45b 100755
--- a/mosk-images/build_image.sh
+++ b/mosk-images/build_image.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -ex
 
-export ENVIRONMENT=${ENVIRONMENT:-'mosk-23.3'}
+export ENVIRONMENT=${ENVIRONMENT:-'23.3'}
 
 source env/${ENVIRONMENT}.sh
 export VM_NAME=${VM_NAME:-"${ENVIRONMENT}-amd64-$(date +"%Y%m%d%H%M%S").qcow2"}