Fix dialyzer error in ebucketmigrator.
Fix dialyzer error in ebucketmigrator.

Change-Id: I8a62e1153655d1cb5c06aa4a66aff1969e287f9d
Reviewed-on: http://review.membase.org/5341
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

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