Fix regression introduced in 1d95edd5922dd74fb4ea00b6b2b9e31a7f5f7657

build.gradle

@@ -30,7 +30,7 @@ repositories {
 }
 
 if (System.getenv('TRAVIS') != null) {
-    if (System.env.TRAVIS_TAG != null) {
+    if (System.env.TRAVIS_TAG != null && System.env.TRAVIS_TAG != "") { // Strangely it has to be both, because it's sometimes set as TRAVIS_TAG="" when we're in travis but no tag is set
         // v3.3.0-stable-sdk1 becomes 3.3.0-stable
         // Intentionally not using lastIndexOf here, we want the second "-".
         ext.jmeEngineVersion = System.env.TRAVIS_TAG.substring(1, System.env.TRAVIS_TAG.indexOf("-", System.env.TRAVIS_TAG.indexOf("-") + 1));