sysmobts: Handle options before allocating the bts
sysmobts: Handle options before allocating the bts

This way -h/--version will always work, even when the underlying
hardware is not available.

telenoobie/osmo-bts,telenoobie/osmo-bts,shimaore/osmo-bts,geosphere/osmo-bts,shimaore/osmo-bts,geosphere/osmo-bts,shimaore/osmo-bts,osmocom/osmo-bts,geosphere/osmo-bts,geosphere/osmo-bts,telenoobie/osmo-bts,osmocom/osmo-bts,telenoobie/osmo-bts,shimaore/osmo-bts,osmocom/osmo-bts