On error, do not list all commands, but point to --help option

- Remove out call to list_common_cmds_help()
- Send error message to stderr, not stdout.

Signed-off-by: Jari Aalto <jari.aalto@cante.net>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

help.c

@@ -185,8 +185,7 @@ static void show_man_page(const char *git_cmd)
 
 void help_unknown_cmd(const char *cmd)
 {
-	printf("git: '%s' is not a git-command\n\n", cmd);
-	list_common_cmds_help();
+	fprintf(stderr, "git: '%s' is not a git-command. See --help\n\n", cmd);
 	exit(1);
 }