VPP-1505 VPP-1508 Remove dep.: py_lispnetworking

VPP-1505 VPP-1508 Remove dep.: py_lispnetworking

test_lisp.py No longer needs the external dependency to run.

py27 runtests: commands[6] | stestr --test-path ./test run --slowest test_lisp
==============================================================================
Basic LISP test
==============================================================================
{0} test.test_lisp.TestLisp.test_lisp_basic_encap [0.487960s] ... ok

======
Totals
======
Ran: 1 tests in 18.0000 sec.
 - Passed: 1
 - Skipped: 0
 - Expected Fail: 0
 - Unexpected Success: 0
 - Failed: 0
Sum of execute time for each test: 0.4880 sec.

==============
Worker Balance
==============
 - Worker 0 (1 tests) => 0:00:00.487960
Test id                                        Runtime (s)
---------------------------------------------  -----------
test.test_lisp.TestLisp.test_lisp_basic_encap  0.488
______________________________________________________ summary ______________________________________________________
  py27: commands succeeded
  congratulations :)
vagrant@vpp:/vpp$

Change-Id: I35b35f8ddaed79066b3ed62fa0460c9ea83273c2
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>