Revert "[update_engine] use libchromeos.pc"

This reverts commit 1723d400f773dc5e341d41928e4f4ea1921e80fb

Change-Id: Ic335b2c2cd863d9f32f24cb311a7e3efea05b475
Reviewed-on: https://gerrit.chromium.org/gerrit/14117
Reviewed-by: Scott James Remnant <keybuk@chromium.org>
Tested-by: Scott James Remnant <keybuk@chromium.org>
diff --git a/SConstruct b/SConstruct
index bda72dc..d73c4e8 100644
--- a/SConstruct
+++ b/SConstruct
@@ -223,7 +223,7 @@
 pkgconfig = os.environ.get('PKG_CONFIG', 'pkg-config')
 
 env.ParseConfig(pkgconfig + ' --cflags --libs '
-                'dbus-1 dbus-glib-1 gio-2.0 gio-unix-2.0 glib-2.0 libchromeos')
+                'dbus-1 dbus-glib-1 gio-2.0 gio-unix-2.0 glib-2.0')
 env.ProtocolBuffer('update_metadata.pb.cc', 'update_metadata.proto')
 env.PublicKey('unittest_key.pub.pem', 'unittest_key.pem')
 env.PublicKey('unittest_key2.pub.pem', 'unittest_key2.pem')