contrib/blacklist: Fix usage for blacklistd/blacklistctl

[jlduran_gmail.com]

Summary

If getopt(3) encounters a character not found in optstring or if it detects a missing option argument, it returns ? (question mark).

It avoids:

$ blacklistd -X
blacklistd: illegal option -- X
blacklistd: Unknown option `?'
Usage: blacklistd ...

Obtained from: https://github.com/zoulasc/blocklist/commit/168ab3042320ff6047fbc2d2cfcce7293ca0974b and https://github.com/zoulasc/blocklist/commit/1b709eaa138eedb3e6e416466f63c722688fc1cb

[jlduran_gmail.com]

Update diff to include context.

[emaste]

contrib/blacklist/bin/blacklistd.c

477

This is still usage(c); upstream it looks like?

[jlduran_gmail.com]

Update with the right diff.

[jlduran_gmail.com]

contrib/blacklist/bin/blacklistd.c

477

Yes, I made a mistake when dissecting from https://github.com/freebsd/freebsd-src/pull/600