Comparing an array to null is not useful, because the expression
will always evaluate as true. Let's just always write SGs server
address and VLR name, no mater whether default values are used
or not, same as we do for the HLR address and port.
Change-Id: If045e42fca0315b0777eb86c44bf934ce58b340b
Fixes: CID#190871 Array compared against 0 (NO_EFFECT)
Add an SGs interface (3GPP TS 29.118) to osmo-msc in order to support
SMS tunneling and Circuit Switched Fallback (CSFB)
Change-Id: I73359925fc1ca72b33a1466e6ac41307f2f0b11d
Related: OS#3615