MB-11005 Lower send/receive buffer sizes for replicators.
MB-11005 Lower send/receive buffer sizes for replicators.

Also make it configurable.

Change-Id: I806b9302175f1abfc87b3e9fe093c4ff989a35b6
Reviewed-on: http://review.couchbase.org/39001
Tested-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

membase/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,mschoch/ns_server,ceejatec/ns_server,membase/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,membase/ns_server,ceejatec/ns_server,nimishzynga/ns_server,ceejatec/ns_server,mschoch/ns_server,mschoch/ns_server,membase/ns_server,membase/ns_server,mschoch/ns_server,mschoch/ns_server,ceejatec/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,membase/ns_server,nimishzynga/ns_server,mschoch/ns_server,ceejatec/ns_server,nimishzynga/ns_server,nimishzynga/ns_server