Set https.protocols when running with JDK 7

Jenkinsfile

@@ -92,7 +92,7 @@ for (String os in runITsOses) {
                             junitPublisher(ignoreAttachments: false)
                         ]) {
                             String cmd = "${runITscommand} -DmavenDistro=$WORK_DIR/apache-maven-dist.zip -Dmaven.test.failure.ignore=true"
-                            if (jdk == '7') {
+                            if (stageId.endsWith('-jdk7')) {
                               // Java 7u80 has TLS 1.2 disabled by default: need to explicitly enable
                               cmd = "${cmd} -Dhttps.protocols=TLSv1.2"
                             }