Turn on -Werror for recovery

Also remove the 0xff comparison when validating the bootloader
message fields. As the fields won't be erased to 0xff after we
remove the MTD support.

Bug: 28202046
Test: The recovery folder compiles for aosp_x86-eng
Change-Id: Ibb30ea1b2b28676fb08c7e92a1e5f7b6ef3247ab
diff --git a/edify/Android.mk b/edify/Android.mk
index 71cf765..b397045 100644
--- a/edify/Android.mk
+++ b/edify/Android.mk
@@ -16,6 +16,7 @@
 		$(edify_src_files) \
 		main.cpp
 
+LOCAL_CFLAGS := -Werror
 LOCAL_CPPFLAGS := -g -O0
 LOCAL_MODULE := edify
 LOCAL_YACCFLAGS := -v
@@ -34,6 +35,7 @@
 
 LOCAL_SRC_FILES := $(edify_src_files)
 
+LOCAL_CFLAGS := -Werror
 LOCAL_CPPFLAGS := -Wno-unused-parameter
 LOCAL_CPPFLAGS += -Wno-deprecated-register
 LOCAL_MODULE := libedify