avahi: remove unused perl dependency

Perl is only required for doxygen which we don't use here
and xmltoman which we don't even package. In any case if
it was used it should have been in nativeBuildInputs, not
buildInputs like now.

pkgs/development/libraries/avahi/default.nix

@@ -5,7 +5,6 @@
 , pkg-config
 , libdaemon
 , dbus
-, perlPackages
 , libpcap
 , expat
 , gettext
@@ -105,10 +104,7 @@ stdenv.mkDerivation rec {
     expat
     libiconv
     libevent
-  ] ++ (with perlPackages; [
-    perl
-    XMLParser
-  ]) ++ lib.optionals stdenv.isFreeBSD [
+  ] ++ lib.optionals stdenv.isFreeBSD [
     libpcap
   ] ++ lib.optionals gtk3Support [
     gtk3