fix bad "licence" names

Mostly what I merged from @lovek323.
Such errors can be easily checked by
  nix-env -f . -qa \* --meta --xml --drv-path --show-trace >/dev/null

pkgs/applications/audio/cd-discid/default.nix

@@ -19,7 +19,7 @@ in
 
     meta = {
       homepage = http://lly.org/~rcw/cd-discid/;
-      licence = "GPLv2+";
+      license = "GPLv2+";
       description = "cd-discid, a command-line utility to retrieve a disc's CDDB ID";
 
       longDescription = ''
@@ -28,4 +28,4 @@ in
         abcde), but can be used for any purpose requiring CDDB data.
       '';
     };
-  }
+  }