Don't die if a version.config already exists...

Change-Id: Ia97e090fa7a5cf46a77eee7bbb1d5ecea9b877fc
Reviewed-on: http://gerrit.dmdirc.com/4038
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager

build.gradle

@@ -104,7 +104,8 @@ task createVersionConfig << {
 
     // Copy to the build directory so it's accessible during tests
     java.nio.file.Files.copy(targetFile.toPath(),
-       sourceSets.main.output.classesDir.toPath().resolve('com').resolve('dmdirc').resolve('version.config'));
+       sourceSets.main.output.classesDir.toPath().resolve('com').resolve('dmdirc').resolve('version.config'),
+       java.nio.file.StandardCopyOption.REPLACE_EXISTING);
 }
 
 jar.dependsOn createVersionConfig