fix null pointer when config file missing

org.eclipse.titan.runtime/src/org/eclipse/titan/runtime/core/mctr/Cli.java

@@ -140,6 +140,11 @@ public class Cli extends UserInterface {
 			System.out.printf("Using configuration file: %s\n", config_file.getName());
 
 			final CfgAnalyzer cfgAnalyzer = new CfgAnalyzer();
+			if (config_file == null) {
+				System.out.println("Error was found in the configuration file. Exiting");
+				cleanUp();
+				return EXIT_FAILURE;
+			}
 			final boolean config_file_failure = cfgAnalyzer.parse(config_file);
 			if (config_file_failure) {
 				System.out.println("Error was found in the configuration file. Exiting");

org.eclipse.titan.runtime/src/org/eclipse/titan/runtime/core/mctr/ConfigData.java

@@ -140,6 +140,9 @@ public class ConfigData {
 
 	//Package-private
 	static String getConfigFileContent(File config_file) {
+		if (config_file == null) {
+			return "";
+		}
 		StringBuilder contentBuilder = new StringBuilder();
 		BufferedReader br = null;