Set default for unset env vars

theodolite-quarkus/src/main/kotlin/theodolite/execution/TheodoliteExecutor.kt

@@ -102,15 +102,11 @@ class TheodoliteExecutor(
     }
 
     private fun getResultFolderString(): String {
-        var resultsFolder: String = System.getenv("RESULTS_FOLDER")
+        var resultsFolder: String = System.getenv("RESULTS_FOLDER") ?: ""
         val createResultsFolder = System.getenv("CREATE_RESULTS_FOLDER") ?: "false"
 
+        if (resultsFolder != ""){
             logger.info { "RESULT_FOLDER: $resultsFolder" }
-
-        if (resultsFolder.isNotEmpty()){
-            resultsFolder += "/"
-        }
-
             val directory = File(resultsFolder)
             if (!directory.exists()) {
                 logger.error { "Folder $resultsFolder does not exist" }
@@ -120,7 +116,8 @@ class TheodoliteExecutor(
                     throw IllegalArgumentException("Result folder not found")
                 }
             }
-        logger.info { "RESULT_FOLDER: $resultsFolder" }
+            resultsFolder += "/"
+        }
         return  resultsFolder
     }