Add fixes for heat deployed UDP_Replay and TRex

- Added a PROTOCOL_MAP to map the protocol names to codes -- the scapy
  requires the code, it fails if the proto is set e.g. to 'udp'
- ip addresses must be str, not unicode -- explicit conversion to str
  added
- removed unittest for setup_vnf_environment in test_tg_trex.py as
  it is the same function as already tested in test_sample_vnf.py
- traffic_profile refactored -- code repetition decreased, unittest
  adapted

Known issues:
- there is a an attempt to stop already stopped trex. It fires an
  exception that stop command is issued on the disconnected client.

Change-Id: I87e9029630f48b30e8f5b4f9d88ab3b25fd65f03
Signed-off-by: Martin Banszel <martinx.banszel@intel.com>