Create the 'postgres' superuser

Old PostgreSQL installations were created using the 'root' database
user. In this case, we need to create a new 'postgres' account, as we
now assume that this is the superuser account.

Unfortunately, these machines will be left with a 'root' user as
well (which will have ownership of some databases). While PostgreSQL
does let you rename superuser accounts, you can only do that when you
are connected as a *different* database user. Thus we'd have to create a
special superuser account to do the renaming. As we default to using
ident authentication, we would have to create a system level user to do
this. This all feels rather complex, so I'm currently opting to keep the
'root' user on these old machines.
Use PostgreSQL 9.3's `pg_isready` to wait for connectivity

The postgresql module has a postStart section that waits for a database
to accept connections before continuing. However, this assumes various
properties about the database - specifically the database user
and (implicitly) the database name. This means that for old
installations, this command fails because there is no 'postgres' user,
and the service never starts.

While 7deff39 does create the 'postgres' user, a better solution is to
use `pg_isready`, who's sole purpose is to check if the database is
accepting connections. This has no dependency on users, so should be
more robust.
gnome-shell: depend upon gnome-settings-daemon gsettings schemas
nixos: add type definitions to virtualisation.libvirtd.* options
Bump Docker to v0.9.1. Tested pulling, committing, pushing.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
haskell-scotty: fix build with new conduit
haskell-libjenkins: fix build with new conduit
Missed file
Merge branch 'postgresql-user-fix' of git://github.com/ocharles/nixpkgs into fix-new-conduit

Create 'postgres' user and use pg_isready
pythonPackages: ipdb, use ipythonLight by default
emacs-idris-mode: upgrade to support idris 0.9.12
Update dd-agent to 4.2.0
Enable the firewall by default

Fixes #2135.
haskellPackages.httpClientMultipart: Do not build haddocks

This package now has no modules, so there is no documentation to build.
The library itself is deprecated, and should probably be removed from
nixpkgs soon.
Don't add users if createUser is false
Remove haskellPackages.aesonLens

This doesn't build, has no reverse dependencies, and the lens library
itself now provides this functionality.
haskell-Elm: require a recent version of binary
flymake-cursor: remove redundant 'meta.platforms = stdenv.lib.platforms.all' setting
flymake-cursor: the sha256 hash of the file has changed

No change was documented on the emacs wiki. Not sure what happened. :-(
ikiwiki: update to version 3.20140227