MB-11903: updated stat names and descriptions for new xdcr stats
MB-11903: updated stat names and descriptions for new xdcr stats

Change-Id: Ic54f819f1d137712e3b3e61cb89eef9a9d24b58f
Reviewed-on: http://review.couchbase.org/40760
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

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