draw spinner on server list while awaiting initial rebalance
draw spinner on server list while awaiting initial rebalance

Without that fix you see 'There are no servers pending rebalance' on
active tab, which is confusing.

Change-Id: I352c76f8c90bb88683b649f3b3e6b114892dc8f4
Reviewed-on: http://review.northscale.com/1221
Reviewed-by: Matt Ingenthron <1fa2ef4755a9226cb9a0a4840bd89b158ac71391@northscale.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

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