jack: change package and attr names to 'jack1' and 'jack2'

Currently, we have a 'jack' package with attrname 'jack1d' and a
'jackdbus' package with attrname 'jackaudio'. Make it consistent 'jack1'
and 'jack2' in both package name and attrname.

This aligns the naming with what can be found on the JACK homepage.

Q: what's the difference between jack1 and jack2?
A: http://trac.jackaudio.org/wiki/Q_differenc_jack1_jack2

pkgs/applications/audio/qjackctl/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, qt4, alsaLib, jackaudio, dbus }:
+{ stdenv, fetchurl, qt4, alsaLib, jack2, dbus }:
 
 stdenv.mkDerivation rec {
   version = "0.3.10";
@@ -11,7 +11,7 @@ stdenv.mkDerivation rec {
     sha256 = "0ch14y3p0x5ss28cpnqcxp42zb2w07d3l1n2sbrkgiz58iy97paw";
   };
 
-  buildInputs = [ qt4 alsaLib jackaudio dbus ];
+  buildInputs = [ qt4 alsaLib jack2 dbus ];
 
   configureFlags = "--enable-jack-version";