Remove unused libbrillo-http dependency.

update_engine doesn't use libbrillo-http for anything. All the HTTP
communication is done directly using libcurl.

Bug: 27178350
TEST=Build on Brillo and Android.

(cherry picked from commit ade107995c68a10f0b2ba23368eeb002efe52771)

Change-Id: I6019d694b979a492ea3954079979d8b5cad227e8
diff --git a/Android.mk b/Android.mk
index 3bca905..468f25a 100644
--- a/Android.mk
+++ b/Android.mk
@@ -63,7 +63,6 @@
     system
 ue_common_shared_libraries := \
     libbrillo \
-    libbrillo-http \
     libbrillo-stream \
     libchrome