Fix bash completion for log driver options

This option was incorrectly ported to the new `daemon` subcommand
structure.

Beside the obvious effect that completion of `docker daemon --log-opt`
did not work, this also caused completion of `docker` and `docker xxx`
to fail on macs with

> bash: words: bad array subscript

Signed-off-by: Harald Albers <github@albersweb.de>

contrib/completion/bash/docker

@@ -342,8 +342,6 @@ _docker_docker() {
 			;;
 	esac
 
-	__docker_complete_log_driver_options && return
-
 	case "$cur" in
 		-*)
 			COMPREPLY=( $( compgen -W "$boolean_options $global_options_with_args" -- "$cur" ) )
@@ -564,6 +562,9 @@ _docker_daemon() {
 			;;
 	esac
 
+	__docker_complete_log_driver_options && return
+
+	# completions for --storage-opt
 	case "${words[$cword-2]}$prev=" in
 		*dm.blkdiscard=*)
 			COMPREPLY=( $( compgen -W "false true" -- "${cur#=}" ) )