contrib/completion/bash/docker: _docker_docker: quoting __docker_to_extglob result to avoid failglob interference

Signed-off-by: Damien Nadé <github@livna.org>

contrib/completion/bash/docker

@@ -606,7 +606,7 @@ _docker_docker() {
 			COMPREPLY=( $( compgen -W "$boolean_options $global_options_with_args" -- "$cur" ) )
 			;;
 		*)
-			local counter=$( __docker_pos_first_nonflag $(__docker_to_extglob "$global_options_with_args") )
+			local counter=$( __docker_pos_first_nonflag "$(__docker_to_extglob "$global_options_with_args")" )
 			if [ $cword -eq $counter ]; then
 				COMPREPLY=( $( compgen -W "${commands[*]} help" -- "$cur" ) )
 			fi