Add bmo_release_branch var ir JJBs for enabling CI in BMO branches

Change-Id: I7e4587b50b68f3d045d04e95a93df30e9bd99ffd
diff --git a/jjb/metal3/job_capm3_e2e_basic_tests.yml b/jjb/metal3/job_capm3_e2e_basic_tests.yml
index 7336ec9..cd7962f 100644
--- a/jjb/metal3/job_capm3_e2e_basic_tests.yml
+++ b/jjb/metal3/job_capm3_e2e_basic_tests.yml
@@ -62,6 +62,10 @@
         default: '{capm3_release_branch}'
         description: 'The target branch of CAPM3 to be used for this test'
     - string:
+        name: bmo_release_branch
+        default: '{bmo_release_branch}'
+        description: 'The target branch of BMO to be used for this test'
+    - string:
         name: CAPI_VERSION
         default: '{capi_version}'
         description: 'Cluster API version. E.g. v1beta1.'