Fix sort order of options in bash completion

See guidelines at the top of the script:

    # Note for developers:
    # Please arrange options sorted alphabetically by long name with the
    # short options immediately following their corresponding long form.
    # This order should be applied to lists, alternatives and code blocks.

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

contrib/completion/bash/docker

@@ -2851,7 +2851,7 @@ _docker_login() {
 
 	case "$cur" in
 		-*)
-			COMPREPLY=( $( compgen -W "--help --password --password-stdin -p --username -u" -- "$cur" ) )
+			COMPREPLY=( $( compgen -W "--help --password -p --password-stdin --username -u" -- "$cur" ) )
 			;;
 	esac
 }