MEDIUM: tools: make str2sa_range() check that the protocol has ->connect()

MEDIUM: tools: make str2sa_range() check that the protocol has ->connect()

Most callers of str2sa_range() need the protocol only to check that it
provides a ->connect() method. It used to be used to verify that it's a
stream protocol, but it might be a bit early to get rid of it. Let's keep
the test for now but move it to str2sa_range() when the new flag PA_O_CONNECT
is present. This way almost all call places could be cleaned from this.

There's a strange test in the server address parsing code that rechecks
the family from the socket which seems to be a duplicate of the previously
removed tests. It will have to be rechecked.