Set connection upr to 0 when closing the connection

If we don't do this then new connections made to a conn struct
that was previously an upr connection will enter the ship_tap_log
state.

Change-Id: I1ea6b515ab1c07b49f44a0efd36446f546844c11
Reviewed-on: http://review.couchbase.org/30006
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>