make check_dir use dir_exists and slightly optimise the latter

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15744 a1c6a512-1295-4272-9138-f99709370657

apps/misc.c

@@ -1115,12 +1115,8 @@ bool file_exists(const char *file)
 bool dir_exists(const char *path)
 {
     DIR* d = opendir(path);
-    bool retval;
-    if (d != NULL) {
-        closedir(d);
-        retval = true;
-    } else {
-        retval = false;
-    }
-    return retval;
+    if (!d)
+        return false;
+    closedir(d);
+    return true;
 }

apps/recorder/recording.c

@@ -590,17 +590,14 @@ static void adjust_cursor(void)
         cursor = max_cursor;
 }
 
-static bool check_dir(char *folder)
+static bool check_dir(const char *folder)
 {
-    DIR *dir = opendir(folder);
-    if (!dir && strcmp(folder, "/"))
+    if (strcmp(folder, "/") && !dir_exists(folder))
     {
         int rc = mkdir(folder);
         if(rc < 0)
             return false;
-        return true;
     }
-    closedir(dir);
     return true;
 }