MB-5224: fixed stat description when showing specific stats
MB-5224: fixed stat description when showing specific stats

I put currently displayed metric's description for specific stats.
And now description available via configuration cell for specific
graphs too.

Change-Id: I008d9c006a814b03860a2ee80c0cdbeaf4e92c37
[76658a2722cfc360b68a81107f0c193549bc08f4@tut.by: corrected commit subject]
Signed-off-by: Aliaksey Kandratsenka <76658a2722cfc360b68a81107f0c193549bc08f4@tut.by>
Reviewed-on: http://review.couchbase.org/15916
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

ceejatec/ns_server,vzasade/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,membase/ns_server,membase/ns_server,t3rm1n4l/ns_server,daverigby/ns_server,mschoch/ns_server,ceejatec/ns_server,daverigby/ns_server,membase/ns_server,mschoch/ns_server,mschoch/ns_server,pavel-blagodov/ns_server,t3rm1n4l/ns_server,mschoch/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,pavel-blagodov/ns_server,mschoch/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,vzasade/ns_server,daverigby/ns_server,mschoch/ns_server,ceejatec/ns_server,vzasade/ns_server,daverigby/ns_server,pavel-blagodov/ns_server,nimishzynga/ns_server,nimishzynga/ns_server,nimishzynga/ns_server,membase/ns_server,vzasade/ns_server,membase/ns_server,daverigby/ns_server,pavel-blagodov/ns_server,ceejatec/ns_server,membase/ns_server