Merge branch 'sb/submodule-deinit-all'

Correct faulty recommendation to use "git submodule deinit ." when
de-initialising all submodules, which would result in a strange
error message in a pathological corner case.

* sb/submodule-deinit-all:
  submodule deinit: require '--all' instead of '.' for all submodules

git-submodule.sh

@@ -8,7 +8,7 @@ dashless=$(basename "$0" | sed -e 's/-/ /')
 USAGE="[--quiet] add [-b <branch>] [-f|--force] [--name <name>] [--reference <repository>] [--] <repository> [<path>]
    or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] init [--] [<path>...]
-   or: $dashless [--quiet] deinit [-f|--force] [--] <path>...
+   or: $dashless [--quiet] deinit [-f|--force] (--all| [--] <path>...)
    or: $dashless [--quiet] update [--init] [--remote] [-N|--no-fetch] [-f|--force] [--checkout|--merge|--rebase] [--reference <repository>] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] summary [--cached|--files] [--summary-limit <n>] [commit] [--] [<path>...]
    or: $dashless [--quiet] foreach [--recursive] <command>
@@ -415,6 +415,7 @@ cmd_init()
 cmd_deinit()
 {
 	# parse $args after "submodule ... deinit".
+	deinit_all=
 	while test $# -ne 0
 	do
 		case "$1" in
@@ -424,6 +425,9 @@ cmd_deinit()
 		-q|--quiet)
 			GIT_QUIET=1
 			;;
+		--all)
+			deinit_all=t
+			;;
 		--)
 			shift
 			break
@@ -438,9 +442,14 @@ cmd_deinit()
 		shift
 	done
 
-	if test $# = 0
+	if test -n "$deinit_all" && test "$#" -ne 0
 	then
-		die "$(eval_gettext "Use '.' if you really want to deinitialize all submodules")"
+		echo >&2 "$(eval_gettext "pathspec and --all are incompatible")"
+		usage
+	fi
+	if test $# = 0 && test -z "$deinit_all"
+	then
+		die "$(eval_gettext "Use '--all' if you really want to deinitialize all submodules")"
 	fi
 
 	git submodule--helper list --prefix "$wt_prefix" "$@" |