vpp_papi: MACAddress equals fails in unittest.

Before:
    EqualsAssertionError:  :: MACAddress(11:22:33:44:55:66) != MACAddress(11:22:33:44:55:66)
    ----------------------------------------------------------------------
    Ran 1 test in 0.002s
    FAILED (failures=1)
    MACAddress(11:22:33:44:55:66) != MACAddress(11:22:33:44:55:66)

After:

    ----------------------------------------------------------------------
    Ran 1 test in 0.001s
    OK

Change-Id: I89896a823b8f8a861813dabf23e7c9207e4fabb6
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>