Bugfix - Set HWT only for first StreamBegin in Recovery

During recovery, HWT for the restarted stream needs to be set
to the point of restart, only for the first stream begin message.
Once it is done, rest of the stream begins can just update the
latest vbuuid.

Change-Id: I98a4aa93e0792267667e45dd2c7e15ea77b50ee8
Reviewed-on: http://review.couchbase.org/43759
Reviewed-by: Deepkaran Salooja <deepkaran.couchbase@gmail.com>
Tested-by: Deepkaran Salooja <deepkaran.couchbase@gmail.com>