Stream: fixed duplicate listen address detection.
Stream: fixed duplicate listen address detection.

The 6f8254ae61b8 change inadvertently fixed the duplicate port
detection similar to how it was fixed for mail in b2920b517490.
It also revealed another issue: the socket type (tcp vs. udp)
wasn't taken into account.

hy0kl/nginx,hy0kl/nginx,hy0kl/nginx