Cleaning up the serialization change.
Renaming the define to be more in line with what it does and removing the host stub header file.

Change-Id: Ibd3a0a6a398c7f81cc661f71e4478707fe1679ed
diff --git a/Android.mk b/Android.mk
index 2d0b6c4..25c8beb 100644
--- a/Android.mk
+++ b/Android.mk
@@ -132,7 +132,7 @@
 
 # Now build a host version for serialization
 include $(CLEAR_VARS)
-LOCAL_CFLAGS += -DANDROID_RS_BUILD_FOR_HOST
+LOCAL_CFLAGS += -DANDROID_RS_SERIALIZE
 
 LOCAL_SRC_FILES:= \
 	rsAllocation.cpp \