bug#17220: SELinux options in --help / manpage may be confusing

[Ondrej Vasik]

Hi,
recently I got one bug report, asking about mknod not running correctly
with old syntax
mknod -m 666 -Z system_u:object_r:random_device_t:s0 /dev/random2 c 1 9
This is not a bug, as since 8.22, short version of -Z doesn't accept
optional arguments.

However, --help and manpage is a bit misleading. I think we should split
the lines for -Z and --context , as both are doing a bit different
thing.
-Z restores the default SELinux context
--context=[CTX] restores the default SELinux context if no CTX is
specified, otherwise sets the SELinux/SMACK context to CTX.

Now, with having them both on one lines, it gives user the feeling that
-Z accepts argument, which may lead to scripts errors. This is not only
about mknod, but about all utilities with -Z option (and recent change
in behaviour)

Thanks in advance for consideration!

Greetings,
         Ondrej