Fixed proguard issues on non-eng builds

Change-Id: Idbfd06cf53c7085081f76873894474cbdbeee874
diff --git a/Android.mk b/Android.mk
index 99f8214..5e545b6 100644
--- a/Android.mk
+++ b/Android.mk
@@ -7,6 +7,8 @@
 
 LOCAL_JNI_SHARED_LIBRARIES := libjni_terminal
 
+LOCAL_PROGUARD_FLAG_FILES := proguard.flags
+
 LOCAL_PACKAGE_NAME := Terminal
 
 include $(BUILD_PACKAGE)