Fix ProGuard errors.

Fix ProGuard error "library class references program class" and
references of org.apache.http.legacy symobls.

Change-Id: I3a6e915b08ca5eabfa863580f489e3bf6b968e9f
diff --git a/Android.mk b/Android.mk
index 97570dc..745a2ad 100644
--- a/Android.mk
+++ b/Android.mk
@@ -32,6 +32,9 @@
 
 LOCAL_PROGUARD_FLAG_FILES := proguard.flags
 
+# Guava uses deprecated org.apache.http.legacy classes.
+LOCAL_JAVA_LIBRARIES += org.apache.http.legacy
+
 LOCAL_JNI_SHARED_LIBRARIES := libjni_tinyplanet libjni_jpegutil
 
 include $(BUILD_PACKAGE)