udisks: add license

pkgs/os-specific/linux/udisks/1-default.nix

···
 
   configureFlags = [ "--localstatedir=/var" "--enable-lvm2" ];
 
-  meta = {
+  meta = with stdenv.lib; {
     homepage = http://www.freedesktop.org/wiki/Software/udisks;
     description = "A daemon and command-line utility for querying and manipulating storage devices";
-    platforms = stdenv.lib.platforms.linux;
+    platforms = platforms.linux;
+    license = with licenses; [ gpl2 lgpl2Plus ];
   };
 }