Remove -h flag from completion and daemon reference
All docker subcommands support `-h` as an alias for `--help`
unless they have `-h` aliased to something else like `docker run`,
which uses `-h` for `--hostname`.
`-h` is not included in the help messages of the commands, though.
It ist visible in
* reference: only in `docker daemon` reference,
see output of `grep -Rse --help=false docs`
* man pages: only in `docker` man page
see output of `grep -RF '**-h**' man`
For consistency reasons, this commit removes `-h` as an alias for
`--help` from the reference page, man page and the bash completion.
Signed-off-by: Harald Albers <github@albersweb.de>