Fix infinite loop in ns_gige stat machine

argh!

dev/ns_gige.cc:
    Exit the state machine so that we don't come right back where
    we started and enter an infinite loop.

--HG--
extra : convert_revision : a5f2b5b5a692de6c80e4b02d7f9bc5d27fe17252

dev/ns_gige.cc

@@ -1929,7 +1929,7 @@ NSGigE::txKick()
                 txState = txFifoBlock;
                 transmit();
 
-                break;
+                goto exit;
             }
 
         }