sc_lastrs is also used in case the sending station is not known, for example in a split IBSS scenario. Therefore always assign sc_lastrs. This removes a hack I committed in r206457.
sc_lastrs is also used in case the sending station is not known, for
example in a split IBSS scenario. Therefore always assign sc_lastrs.
This removes a hack I committed in r206457.

Approved by:	rpaulo (mentor)

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase