Use -Wno-error=date-time

We're actually going to enable -Werror=date-time, not -Wdate-time.

Bug: 24204119
Change-Id: I0df28593e151f566a11b9a1411a33a97a26db6f8
diff --git a/Android.mk b/Android.mk
index 8bcbc4f..739c1b9 100644
--- a/Android.mk
+++ b/Android.mk
@@ -728,7 +728,7 @@
 
 LOCAL_CFLAGS += \
 	$(deqp_compile_flags) \
-	-Wno-date-time
+	-Wno-error=date-time
 
 LOCAL_SDK_VERSION := 9
 LOCAL_CPPFLAGS += -Wno-non-virtual-dtor