JCBC-510: Allow optional non-persistent view connections.

Motivation
----------
With HTTP 1.1, all connections are by default persistent, unless connection
control headers are set to close. In order to provide more flexbility in how
the client handles those connection, an optional system property can be set
to change it appropriately.

Modifications
-------------
A custom system property has been introduced and the view pipeline has been
modified to take it into account. Tests have been added to verify the
header settings.

Result
------
It is now possible to change socket persistence behavior from a system
property.

Change-Id: I960bf22cb64f8fa93ee4853cfff0bd1103d487c2
Reviewed-on: http://review.couchbase.org/40685
Reviewed-by: Matt Ingenthron <matt@couchbase.com>
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>