Don't require 'all' argument to --cmdhelp to dump all options

If an argument isn't given, just dump all commands. This has the
downside that one MUST use --cmdhelp=option to get option help,
where as before --cmdhelp option worked as well.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/parse.c b/parse.c
index d13a603..ee7ddf2 100644
--- a/parse.c
+++ b/parse.c
@@ -439,7 +439,6 @@
 
 int show_cmd_help(struct fio_option *options, const char *name)
 {
-	int show_all = !strcmp(name, "all");
 	const char *typehelp[] = {
 		"string (opt=bla)",
 		"string with possible k/m/g postfix (opt=4k)",
@@ -453,9 +452,16 @@
 	};
 	struct fio_option *o;
 	int found = 0;
+	int show_all = 0;
+
+	if (!name || !strcmp(name, "all"))
+		show_all = 1;
 
 	for (o = &options[0]; o->name; o++) {
-		int match = !strcmp(name, o->name);
+		int match = 0;
+
+		if (name && !strcmp(name, o->name))
+			match = 1;
 
 		if (show_all || match) {
 			found = 1;