Ticket #263: Make sure to compare the correct object types in the group usage test.

extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/service/PermissionCheckService.java

@@ -347,7 +347,8 @@ public class PermissionCheckService {
             return false;
 
         // Verify that the desired usage matches the type.
-        return connectionGroup.getType().equals(usage);
+        return MySQLConstants.getConnectionGroupTypeConstant(
+                connectionGroup.getType()).equals(usage);
         
     }