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/ingen/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchsvn, boost, ganv, glibmm, gtk, gtkmm, jackaudio, lilv
+{ stdenv, fetchsvn, boost, ganv, glibmm, gtk, gtkmm, jack2, lilv
 , lv2, pkgconfig, python, raul, serd, sord, sratom, suil
 }:
 
@@ -13,7 +13,7 @@ stdenv.mkDerivation  rec {
   };
 
   buildInputs = [
-    boost ganv glibmm gtk gtkmm jackaudio lilv lv2 pkgconfig python
+    boost ganv glibmm gtk gtkmm jack2 lilv lv2 pkgconfig python
     raul serd sord sratom suil
   ];