Set the Network Specifier on Emergency SUPL

The sub ID of a SIM that the emergency call
was made on needs to be specified while
requesting a SUPL Emergency connection. This
is done by setting the Network Specifier in
the SUPL Emergency connection request so that
connection is made on the correct sub for a
device that can have more that one SIM.

CRs-fixed: 2563763
Change-Id: I54cac37bfa02ab6b21b4f763c07c54f567c449ff