libvirt: Clean up nix file, update meta

pkgs/development/libraries/libvirt/default.nix

@@ -6,32 +6,38 @@
 
 let version = "1.2.2"; in
 
-stdenv.mkDerivation {
+stdenv.mkDerivation rec {
   name = "libvirt-${version}";
 
   src = fetchurl {
-    url = "http://libvirt.org/sources/libvirt-${version}.tar.gz";
+    url = "http://libvirt.org/sources/${name}.tar.gz";
     sha256 = "1hxvgh2fp2fk3wva7fnbz2pk6g5217wrmf9xwikiphn50zipg0x4";
   };
 
-  buildInputs =
-    [ pkgconfig libxml2 gnutls devicemapper perl python readline lvm2
+  buildInputs = [
+    pkgconfig libxml2 gnutls devicemapper perl python readline lvm2
     utillinux udev libpciaccess gettext libtasn1 libgcrypt yajl makeWrapper
     libcap_ng
   ];
 
-  preConfigure =
-    ''
+  preConfigure = ''
     PATH=${iproute}/sbin:${iptables}/sbin:${ebtables}/sbin:${lvm2}/sbin:${udev}/sbin:${dnsmasq}/bin:$PATH
     patchShebangs . # fixes /usr/bin/python references
   '';
 
-  configureFlags = "--localstatedir=/var --sysconfdir=/etc --with-init-script=redhat --without-macvtap";
+  configureFlags = [
+    "--localstatedir=/var"
+    "--sysconfdir=/etc"
+    "--with-init-script=redhat"
+    "--without-macvtap"
+  ];
 
-  installFlags = "localstatedir=$(TMPDIR)/var sysconfdir=$(out)/etc";
+  installFlags = [
+    "localstatedir=$(TMPDIR)/var"
+    "sysconfdir=$(out)/etc"
+  ];
 
-  postInstall =
-    ''
+  postInstall = ''
     substituteInPlace $out/libexec/libvirt-guests.sh \
       --replace "$out/bin" "${gettext}/bin"
     wrapProgram $out/sbin/libvirtd \
@@ -39,12 +45,16 @@ stdenv.mkDerivation {
   '';
 
   enableParallelBuilding = true;
+
   NIX_CFLAGS_COMPILE = "-fno-stack-protector";
 
-  meta = {
+  meta = with stdenv.lib; {
     homepage = http://libvirt.org/;
-    description = "A toolkit to interact with the virtualization capabilities of recent versions of Linux (and other OSes)";
-    license = "LGPLv2+";
-    platforms = stdenv.lib.platforms.linux;
+    description = ''
+      A toolkit to interact with the virtualization capabilities of recent
+      versions of Linux (and other OSes)
+    '';
+    license = licenses.lgpl2Plus;
+    platforms = platforms.linux;
   };
 }