submodule update: direct error message to stderr

Reroute the error message for specified but initialized submodules
to stderr instead of stdout.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-submodule.sh

@@ -693,7 +693,7 @@ cmd_update()
 
 		if test "$update_module" = "none"
 		then
-			echo "Skipping submodule '$displaypath'"
+			echo >&2 "Skipping submodule '$displaypath'"
 			continue
 		fi
 
@@ -702,7 +702,7 @@ cmd_update()
 			# Only mention uninitialized submodules when its
 			# path have been specified
 			test "$#" != "0" &&
-			say "$(eval_gettext "Submodule path '\$displaypath' not initialized
+			say >&2 "$(eval_gettext "Submodule path '\$displaypath' not initialized
 Maybe you want to use 'update --init'?")"
 			continue
 		fi

t/t7400-submodule-basic.sh

@@ -462,7 +462,7 @@ test_expect_success 'update --init' '
 	git config --remove-section submodule.example &&
 	test_must_fail git config submodule.example.url &&
 
-	git submodule update init > update.out &&
+	git submodule update init 2> update.out &&
 	cat update.out &&
 	test_i18ngrep "not initialized" update.out &&
 	test_must_fail git rev-parse --resolve-git-dir init/.git &&
@@ -480,7 +480,7 @@ test_expect_success 'update --init from subdirectory' '
 	mkdir -p sub &&
 	(
 		cd sub &&
-		git submodule update ../init >update.out &&
+		git submodule update ../init 2>update.out &&
 		cat update.out &&
 		test_i18ngrep "not initialized" update.out &&
 		test_must_fail git rev-parse --resolve-git-dir ../init/.git &&