mkm3u: Actually cross off used titles in `used_titles'.

This would have caught my `Smallville' blunder.

diff --git a/mkm3u b/mkm3u
index b66ad4b..d704856 100755 (executable)
--- a/mkm3u
+++ b/mkm3u
@@ -135,7 +135,7 @@ class Source (object):
   def __init__(me, fn):
     me.fn = fn
     me.neps = None
-    me.used_titles = dict()
+    me.used_titles = set()
     me.used_chapters = set()
     me.nuses = 0
 
@@ -215,7 +215,9 @@ class Source (object):
         else:
           raise ExpectedError("`%s' title %d chapter %d already used" %
                               (me.fn, title, k[1]))
-    if end_chapter != -1:
+    if end_chapter == -1:
+      me.used_titles.add(title)
+    else:
       for ch in range(start_chapter, end_chapter):
         me.used_chapters.add((title, ch))
     return me.PREFIX + ROOT + urlencode(me.fn) + suffix, duration