ACE_INET_Addr::set errantly succeeds when ACE_LACKS_GETSERVBYNAME

Problem
-------

Calling `set("1.2.3.4")` on an ACE_INET_Addr eventually tries to part
it as a port name.  When `ACE_LACKS_GETSERVBYNAME`, this succeeds
returning port number 0 with the reset address.

When port names are not expected, this breaks a useful idiom of
parsing addresses that may or may not contain port numbers:

    ACE_INET_Addr addr;
    if (addr.set(x) == 0) {
      // Success, address contained a port number
    } else if (addr.set(u_short(0), x) == 0) {
      // Success, address did not contain a port number.
    } else {
      // Fail
    }

Solution
--------

Return -1 for the port number when `ACE_LACKS_GETSERVBYNAME`.

ACE/ace/INET_Addr.cpp

@@ -468,12 +468,11 @@ static int get_port_number_from_name (const char port_name[],
     }
 
   // We try to resolve port number from its name.
+  port_number = -1;
 #if defined (ACE_LACKS_GETSERVBYNAME)
-  port_number = 0;
   ACE_UNUSED_ARG (port_name);
   ACE_UNUSED_ARG (protocol);
 #else
-  port_number = -1;
   servent sentry;
   ACE_SERVENT_DATA buf;
   servent *sp = ACE_OS::getservbyname_r (port_name,