fixing pipeline script bug in xos-sync-update

Change-Id: Ie3cf1b537dbf6f0e82be0d7897ef6d936fda852b
diff --git a/jjb/pipeline/xos-synchronizer-update.groovy b/jjb/pipeline/xos-synchronizer-update.groovy
index af154c9..d2cdfda 100644
--- a/jjb/pipeline/xos-synchronizer-update.groovy
+++ b/jjb/pipeline/xos-synchronizer-update.groovy
@@ -117,7 +117,7 @@
 
            for df in cord/orchestration/xos_services/*/Dockerfile.synchronizer cord/orchestration/profiles/*/Dockerfile.synchronizer
            do
-             df_contents=$(cat "\$df")
+             df_contents=\$(cat "\$df")
              if [[ "\$df_contents" =~ "FROM xosproject/xos-synchronizer-base:\${XOS_MAJOR}" ||
                    "\$df_contents" =~ "FROM xosproject/xos-synchronizer-base:master" ]]
              then