Fixed minor format errors and resource leaks

Some format strings used integer values for unsigned integers.
Memory and file descriptors leaked in some error conditions.

server/modules/filter/dbfwfilter.c

@@ -1242,6 +1242,7 @@ createInstance(char **options, FILTER_PARAMETER **params)
     if ((my_instance = calloc(1, sizeof(FW_INSTANCE))) == NULL ||
         (my_instance->lock = (SPINLOCK*) malloc(sizeof(SPINLOCK))) == NULL)
     {
+        free(my_instance);
         MXS_ERROR("Memory allocation for firewall filter failed.");
         return NULL;
     }

server/modules/filter/slavelag.c

@@ -199,7 +199,7 @@ int		i,cflags = 0;
 			else
 			{
 			    MXS_ERROR("lagfilter: unsupported option '%s'.",
-                                      options[i])));
+                                      options[i]);
 			}
 		    }
 		}