set zero shutdown timeout for eng build

- still it will take time to kill services, < 3 secs in tested device.

bug: 36678028
Test: reboot

(cherry picked from commit 56425ed87e1ad7c63437d67c3b17ed7e2ba8d340)

Change-Id: I75b5843b08cdcdbf67c4fe500aa0dd7302dd44d7
diff --git a/init/Android.mk b/init/Android.mk
index b52c949..1ca88d7 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -16,6 +16,14 @@
     -DREBOOT_BOOTLOADER_ON_PANIC=0
 endif
 
+ifneq (,$(filter eng,$(TARGET_BUILD_VARIANT)))
+init_options += \
+    -DSHUTDOWN_ZERO_TIMEOUT=1
+else
+init_options += \
+    -DSHUTDOWN_ZERO_TIMEOUT=0
+endif
+
 init_options += -DLOG_UEVENTS=0
 
 init_cflags += \