nvmeofgw: fix sending acks during upgrade

nvmeofgw: fix sending acks during upgrade
          fix gw-epoch during upgrade
          1.fixed issue  when during upgrade before feature NVMEOFHAMAP is
          applyed, monitor did not send acks to beacon - this cause
          expiration GW mon-client beacon ack timeout and assert of the GW.
          2. fixed issue that during upgrade new GW epoch, generated
	  after applying of new feature NVMEOFHAMAP was less than
	  global epoch. So GW mon-client asserted on receiving new epoch
          that is less than its last received epoch

Signed-off-by: Leonid Chernin <leonidc@il.ibm.com>