fix lock grab on releasing a non-existent lock

CHANGELOG

@@ -4,6 +4,7 @@
     - addition of optional comment fields on edit
     - cache-based lock for writing
     - added MARKUPWIKI_ settings
+    - RSS for articles and wiki as a whole
 
 0.1.0
 =====

TODO

@@ -1,8 +1,6 @@
 * revert option
 * wikiword highlighting
 * detect broken wiki links
+* tests
 * only store diffs?
 * anonymous edits?
-
-add options:
-    * MARKUPWIKI_WIKIWORD_RE

markupwiki/models.py

@@ -68,7 +68,8 @@ class Article(models.Model):
                 cache.delete(cache_key)
             return lock == user.id
 
-        cache.set(cache_key, user.id, WRITE_LOCK_SECONDS)
+        if not release:
+            cache.set(cache_key, user.id, WRITE_LOCK_SECONDS)
         return True
 
 class ArticleVersion(models.Model):