Delete .developer_mode after in-place wiping

After in-place wiping, clobber-state put .developer_mode in stateful
partition. This causes an unexpected 'return from dev mode' screen on
the next boot. Remove this file after running clobber-state.

BUG=chrome-os-partner:49058
TEST=Run in-place wipe and boot again into normal mode.

Change-Id: I58519e9ab19a3ebc952c0e2de68157c13c33a306
Reviewed-on: https://chromium-review.googlesource.com/320902
Commit-Ready: Shun-Hsing Ou <shunhsingou@chromium.org>
Tested-by: Shun-Hsing Ou <shunhsingou@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Bowgo Tsai <bowgotsai@chromium.org>
(cherry picked from commit 0a2e143adc9c1dfb1d97603092172ab21f6723aa)
Reviewed-on: https://chromium-review.googlesource.com/321221
Reviewed-by: Shun-Hsing Ou <shunhsingou@chromium.org>
Commit-Queue: Shun-Hsing Ou <shunhsingou@chromium.org>
diff --git a/sh/wipe_init.sh b/sh/wipe_init.sh
index 9fec5d9..8b38f23 100755
--- a/sh/wipe_init.sh
+++ b/sh/wipe_init.sh
@@ -71,6 +71,9 @@
     FACTORY_RETURN_AFTER_WIPING="YES" clobber-state "${WIPE_ARGS}"
   mv -f "/tmp/clobber-state.log" "${STATE_PATH}/unencrypted/clobber-state.log"
 
+  # Remove developer flag, which is created by clobber-state after wiping.
+  rm -f "${STATE_PATH}/.developer_mode"
+
   "${ENABLE_RELEASE_PARTITION}" "${release_root_dev}"
 
   # TODO(shunhsingou): need to inform shopfloor here.