(Only the first 10 of 42 ports in this commit are shown above. )
Remove USE_GPG from all effected ports. This knob is a no-op and the way it
was supposed to work is useless, because if we can't trust the distfile from
the remote machine, we can't trust the signature from the same machine either.
Our MD5 and SHA256 are good for checking both the sanity and the
trustiness of distfiles.
Approved by: portmgr (erwin), erwin (mentor)