serf: Delete env config file

net-libs/serf package has been removed from Chrome OS for a while.
Remove the leftover env config file.

BUG=None
TEST=CQ

Change-Id: I61637f8195289475e97f5a726b6975c3ff7d2dca
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/2596231
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
diff --git a/chromeos/config/env/net-libs/serf b/chromeos/config/env/net-libs/serf
deleted file mode 100644
index fefcf91..0000000
--- a/chromeos/config/env/net-libs/serf
+++ /dev/null
@@ -1,9 +0,0 @@
-# Copyright 2016 The Chromium OS Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-# The build is all messed up.  https://crbug.com/577836
-# and https://crbug.com/656818
-cros_pre_src_compile_use_gcc() {
-	unset CC CXX
-}