Fix typo in OMEC license check manual run

Change-Id: I3830ed309148545ff56a2cf7b39a30a0c36bcce2
diff --git a/jjb/pipeline/omec-fossa-scan.groovy b/jjb/pipeline/omec-fossa-scan.groovy
index a6c2169..c70f3eb 100644
--- a/jjb/pipeline/omec-fossa-scan.groovy
+++ b/jjb/pipeline/omec-fossa-scan.groovy
@@ -71,7 +71,7 @@
                         #!/usr/bin/env bash
 
                         cd ${params.project}
-                        if [ ! -Z ${params.ghprbPullId} ]
+                        if [ ! -z ${params.ghprbPullId} ]
                         then
                           git checkout FETCH_HEAD
                         else