CI: fix in pipeline

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

ci-scripts/Jenkinsfile-gitlab

@@ -57,7 +57,9 @@ pipeline {
 
                     echo '\u2705 \u001B[32mVerify Parameters\u001B[0m'
                     def allParametersPresent = true
-                    echo "Platform is ${TESTPLATFORM_OWNER}"
+                    if (${TESTPLATFORM_OWNER} != null) {
+                        echo "Platform is ${TESTPLATFORM_OWNER}"
+                    }
 
                     if (params.RedHatRemoteServer == null) {
                         allParametersPresent = false