various: fix memory leaks

Closes: #41

udev_device.c

@@ -546,12 +546,14 @@ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *
     }
 
     if (!realpath(syspath, path)) {
+        free(subsystem);
         return NULL;
     }
 
     udev_device = calloc(1, sizeof(*udev_device));
 
     if (!udev_device) {
+        free(subsystem);
         return NULL;
     }
 

udev_list.c

@@ -78,6 +78,7 @@ struct udev_list_entry *udev_list_entry_add(struct udev_list_entry *list_entry,
     list_entry2->name = strdup(name);
 
     if (!list_entry2->name) {
+        free(list_entry2);
         return NULL;
     }
 
@@ -85,6 +86,8 @@ struct udev_list_entry *udev_list_entry_add(struct udev_list_entry *list_entry,
         list_entry2->value = strdup(value);
 
         if (!list_entry2->value) {
+            free(list_entry2->name);
+            free(list_entry2);
             return NULL;
         }
     }