common: Declare explicit Vector move constructor
common: Declare explicit Vector move constructor

Vector class already has a semantically odd non-const copy
constructor that serves the same function as a C++11 move
constructor. Make the move constructor semantics explicit
and address Coverity at the same time.

Change-Id: I22e0099abe601b0c59beee808f7560837c6977dd
Fixes: Coverity CID 170738

ttsou/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx,ttsou/osmo-trx,ttsou/osmo-trx,ttsou/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx