haskell-bindings-posix: fix bogus change committed earlier
Partially revert commit 075796e0531506fa106be1d2f47a9c866b70b99c.

The commit downgraded the german language dictionary from version 20030222-1 to
20120607 (and broke the build in the process). That change was probably not
intended?
pkgs/development/libraries/aspell/dictionaries.nix: strip trailing whitespace