Log Message:
* Release 1.8.3 (2011-09-13)

** Security-related Bugfix

 - Fix flaw that would allow a person who knows a storage index of a file to
   delete shares of that file (#1528).
 - Remove corner cases in mutable file bounds management which could expose
   extra lease info or old share data (from prior versions of the mutable
   file) if someone with write authority to that mutable file exercised these
   corner cases in a way that no actual Tahoe-LAFS client does. (Probably not
   exploitable.) (#1528).