fix build blocker regex on omec jobs

Change-Id: I6a44ef2da7bafc0c73f3ca2c405ced7dea447334
diff --git a/jjb/omec-ci.yaml b/jjb/omec-ci.yaml
index e26be3a..f9cabc7 100644
--- a/jjb/omec-ci.yaml
+++ b/jjb/omec-ci.yaml
@@ -86,7 +86,7 @@
       - build-blocker:
           use-build-blocker: true
           blocking-jobs:
-            - "omec-combined"
+            - "omec_.*_combined"
 
     wrappers:
       - lf-infra-wrappers: