Dropped obsolete Haskell packages.

- convertible-text: deprecated by author
 - failure: obsolete version 0.1.2
 - attempt: obsolete version 0.3.1.1

svn path=/nixpkgs/trunk/; revision=33470

pkgs/development/libraries/haskell/attempt/0.3.1.1.nix

@@ -1,15 +0,0 @@
-{ cabal, failure }:
-
-cabal.mkDerivation (self: {
-  pname = "attempt";
-  version = "0.3.1.1";
-  sha256 = "0yfn8mh7gy6nh689ic6sygf9d7lk44kpj2wahnljl53k6vw7smv5";
-  buildDepends = [ failure ];
-  meta = {
-    homepage = "http://github.com/snoyberg/attempt/tree/master";
-    description = "Concrete data type for handling extensible exceptions as failures";
-    license = self.stdenv.lib.licenses.bsd3;
-    platforms = self.ghc.meta.platforms;
-    maintainers = [ self.stdenv.lib.maintainers.andres ];
-  };
-})