increase ebucketmigrator upstream timeout to 5 minutes
increase ebucketmigrator upstream timeout to 5 minutes

Because sometimes when tap producer is very busy with fetching things
from disk, 30 seconds might be not enough.

Change-Id: I1d51233ec5bd6ba8d5a8e926afa422baf08c301f
Reviewed-on: http://review.membase.org/6573
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

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