ofpbuf: Simplify ofpbuf API.

ofpbuf was complicated due to its wide usage across all
layers of OVS, Now we have introduced independent dp_packet
which can be used for datapath packet, we can simplify ofpbuf.
Following patch removes DPDK mbuf and access API of ofpbuf
members.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>

tests/test-bundle.c

@@ -76,7 +76,7 @@ parse_bundle_actions(char *actions)
         ovs_fatal(0, "%s", error);
     }
 
-    action = ofpbuf_data(&ofpacts);
+    action = ofpacts.data;
     bundle = ofpact_get_BUNDLE(xmemdup(action, action->len));
     ofpbuf_uninit(&ofpacts);