MB-11834: Use Host:Port as node list format

Similar to failover case, all nodes to collect logs should be specified
in HOST[:PORT] format separated by character ':'. If no port number
specified, default 8091 will be used.

Change-Id: Ib86dd82818758710bffe45736717d58610303e1b
Reviewed-on: http://review.couchbase.org/39980
Tested-by: Bin Cui <bin.cui@gmail.com>
Reviewed-by: Steve Yen <steve.yen@gmail.com>