* Don't copy features for osmo-bts and nanobts initially, wait until
BTS reported its features
* Checks for BTS features in VTY cmds: pass if features are not known
(not yet reported by the BTS), fail if the feature is missing
* Once BTS reports its features, check relevant VTY config parts again
Related: SYS#5922, OS#5538
Change-Id: I7fca42a39a4bc98a6ea8b9cfab28c4bad3a6a0aa
