android: Remove/filter header files from LOCAL_SRC_FILES

This avoids huge warnings when building the native code.

src/scepclient/Android.mk

@@ -2,9 +2,11 @@ LOCAL_PATH := $(call my-dir)
 include $(CLEAR_VARS)
 
 # copy-n-paste from Makefile.am
-LOCAL_SRC_FILES := \
+scepclient_SOURCES := \
 scepclient.c scep.c scep.h
 
+LOCAL_SRC_FILES := $(filter %.c,$(scepclient_SOURCES))
+
 # build scepclient -------------------------------------------------------------
 
 LOCAL_C_INCLUDES += \