bond: fix vlan flag interpretation

bond: fix vlan flag interpretation

This patch contains a fix for link bonding handling of vlan tagged packets in mode 3 and 5.
Currently xmit_slave_hash function misinterprets the PKT_RX_VLAN_PKT flag to mean that
there is a vlan tag within the packet when in actually means that there is a valid entry
in the vlan_tci field in the mbuf.

- Fixed VLAN tag support in hashing functions.
- Adds support for TCP in layer 4 header hashing.
- Splits transmit hashing function into separate functions for each policy to
  reduce branching and to make the code clearer.
- Fixed incorrect flag set in test application packet generator.

Test report: http://dpdk.org/ml/archives/dev/2015-January/010792.html

Signed-off-by: Declan Doherty <declan.doherty@intel.com>
Acked-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Tested-by: SunX Jiajia <sunx.jiajia@intel.com>