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/tools/misc/timidity/default.nix

@@ -1,4 +1,4 @@
-{ composableDerivation, stdenv, fetchurl, alsaLib, jackaudio, ncurses }:
+{ composableDerivation, stdenv, fetchurl, alsaLib, jack2, ncurses }:
 
 let inherit (composableDerivation) edf; in
 
@@ -30,8 +30,8 @@ composableDerivation.composableDerivation {} {
     };
     jack = {
       audioModes = "jack";
-      buildInputs = [jackaudio];
-      NIX_LDFLAGS = ["-ljack -L${jackaudio}/lib64"];
+      buildInputs = [jack2];
+      NIX_LDFLAGS = ["-ljack -L${jack2}/lib64"];
     };
   } // edf { name = "ncurses"; enable = { buildInputs = [ncurses]; };};