MB-5385: fixed standalone bucketmigrator to support sasl auth
MB-5385: fixed standalone bucketmigrator to support sasl auth

So that it's possible to replicate & takeover non-default bucket. I've
also made it stop advertising vbucketmigrator flags it doesn't
understand. And made -v flag work by lowering log level to debug.

Change-Id: I7c76b23c1aa629d2b336f802e70e8b003c6ebffb
Reviewed-on: http://review.couchbase.org/16447
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

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