str2listener() was temporarily hacked to support datagram sockets for
the log-forward listeners. This has has an undesirable side effect that
"bind udp@1.2.3.4:5555" was silently accepted as TCP for a bind line.
We don't need this hack anymore since the only user (log-forward) now
relies on str2receiver(). Now such an address will properly be rejected.
Now str2sa_range() will enforce the caller's port specification passed
using the PA_O_PORT_* flags, and will return an error on failure. For
optional ports, values 0-65535 will be enforced. For mandatory ports,
values 1-65535 are enforced. In case of ranges, it is also verified that
the upper bound is not lower than the lower bound, as this used to result
in empty listeners.
I couldn't find an easy way to test this using VTC since the purpose is
to trigger parse errors, so instead a test file is provided as
tests/ports.cfg with comments about what errors are expected for each
line.
