GSUP client: send CN domain IE on LU request

Give the HLR a chance to send us updated subscriber data by indicating the CN
domain to be Circuit Switched, only during a LU Request GSUP message.

Adjust msc_vlr_tests to expect the added GSUP CN domain IE to indicate CS, i.e.
append '280102'.

Related: OS#3601
Change-Id: I0c2d33fbfdb4728e480679120d06b7f3a2ccfd76
25 files changed