Merge branch 'rr/maint-submodule-unknown-cmd' into maint

"git submodule frotz" was not diagnosed as "frotz" being an unknown
subcommand to "git submodule"; the user instead got a complaint that
"git submodule status" was run with an unknown path "frotz".

* rr/maint-submodule-unknown-cmd:
  submodule: if $command was not matched, don't parse other args

Author: gitster

Documentation/git-submodule.txt

@@ -112,7 +112,6 @@ status::
 	initialized, `+` if the currently checked out submodule commit
 	does not match the SHA-1 found in the index of the containing
 	repository and `U` if the submodule has merge conflicts.
-	This command is the default command for 'git submodule'.
 +
 If `--recursive` is specified, this command will recurse into nested
 submodules, and show their status as well.

git-submodule.sh

@@ -1107,7 +1107,15 @@ do
 done
 
 # No command word defaults to "status"
-test -n "$command" || command=status
+if test -z "$command"
+then
+    if test $# = 0
+    then
+	command=status
+    else
+	usage
+    fi
+fi
 
 # "-b branch" is accepted only by "add"
 if test -n "$branch" && test "$command" != add

t/t7400-submodule-basic.sh

@@ -438,8 +438,8 @@ test_expect_success 'moving to a commit without submodule does not leave empty d
 	git checkout second
 '
 
-test_expect_success 'submodule <invalid-path> warns' '
-	test_failure_with_unknown_submodule
+test_expect_success 'submodule <invalid-subcommand> fails' '
+	test_must_fail git submodule no-such-subcommand
 '
 
 test_expect_success 'add submodules without specifying an explicit path' '