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>

man/docker.1.md

@@ -23,7 +23,7 @@ its own man page which explain usage and arguments.
 To see the man page for a command run **man docker <command>**.
 
 # OPTIONS
-**-h**, **--help**
+**--help**
   Print usage statement
 
 **--api-cors-header**=""