all-packages.nix: fix typos in the haskellPackages attribute sets for GHC 7.4.2
all-packages.nix: fix typos in the haskellPackages attribute sets for GHC 7.4.2

The haskellPackages_ghc742_{no_,}profiling set accidentally referred to
the GHC 7.4.1 versions.

SymbiFlow/nixpkgs,triton/triton,SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,triton/triton,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,triton/triton,triton/triton,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,triton/triton,NixOS/nixpkgs,triton/triton,SymbiFlow/nixpkgs,triton/triton,SymbiFlow/nixpkgs,triton/triton,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs