[analytics.js] correctly append updated samples
[analytics.js] correctly append updated samples

menelaus_stats actually includes lastTStamp sample in it's stats
update response, so should not append it again

Change-Id: Ica52d8828d5fad76aebf067ea00fd5893d4a0ce5
Reviewed-on: http://review.northscale.com/1156
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

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