transaction: reset transaction on abort

Prevent the use of the transaction after it has been aborted.

Co-contributor: Sune Foldager <[e-mail]>

mercurial/transaction.py

@@ -94,6 +94,9 b' class transaction(object):'
         self._abort()
 
     def _abort(self):
+        self.count = 0
+        self.file.close()
+
         if not self.entries: return
 
         self.report(_("transaction abort!\n"))
@@ -109,13 +112,14 b' class transaction(object):'
         self.entries = []
 
         if not failed:
-            self.file.close()
             os.unlink(self.journal)
-            self.journal = None
             self.report(_("rollback completed\n"))
         else:
             self.report(_("rollback failed - please run hg recover\n"))
 
+        self.journal = None
+
+
 def rollback(opener, file):
     files = {}
     for l in open(file).readlines():