Fix another small whitespace issue

build.gradle

@@ -50,7 +50,7 @@ public class Version
 {
   public static final String VERSION = "${project.version}";
 }
-    """
+"""
     File f = file("src/main/java/org/sablecc/sablecc/Version.java")
     f.delete()
     f <<  buildconstants_class