Remove useless static linking

LOCAL_STATIC_LIBRARIES in a BUILD_STATIC_LIBRARY only imports C include
directories, it doesn't actually do any linking. Since this module is
building against the NDK, it shouldn't be referencing modules not built
against the NDK, like libprotobuf-cpp-lite. There are versions of that
library that may be more appropriate, but since there aren't any source
files, we don't need the include directories, so remove it entirely.

Change-Id: I47f7333228bea43979ce86c4bd23f4b2a92b49ce
diff --git a/Android.mk b/Android.mk
index f811331..68f756f 100644
--- a/Android.mk
+++ b/Android.mk
@@ -98,9 +98,6 @@
     libwebrtc_isacfix_neon_gnustl_static
 endif
 
-LOCAL_STATIC_LIBRARIES := \
-    libprotobuf-cpp-lite
-
 LOCAL_NDK_STL_VARIANT := gnustl_static
 LOCAL_SDK_VERSION := 14