Changes

xua_asp_fsm: Error on ASP UP (ACK) with non-unique ASP Identifier

Following RFC4666:
"""
   The "Invalid ASP Identifier" error is sent by an SGP in response to
   an ASP Up message with an invalid (i.e., non-unique) ASP Identifier
"""

Change-Id: I2d422acaa2f04c7d1eebd92c3185c4f5476a1789