firmware_ConsecutiveBoot: Add cleanup to clear GBB_FLAG_DEV_SCREEN_SHORT_DELAY

In developer mode test, we are changing the GBB flag to
GBB_FLAG_DEV_SCREEN_SHORT_DELAY in initialize function to boot the device
with short dev screen delay.

But GBB_FLAG_DEV_SCREEN_SHORT_DELAY flag is not cleared at the end of test.
And this will affects the tests in restore_mode when test started in
Normal mode.

BUG=None
Branch=None
TEST= Verified firmware_ConsecutiveBoot.dev test on Soraka board, test is
passing.

Change-Id: I8fa32436d03dc04d90de7042524b85eeecea38b9
Signed-off-by: Lenine Ajagappane <leninex.ajagappane@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/1065957
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Naresh Solanki <naresh.solanki@intel.com>
Reviewed-by: Naresh Solanki <naresh.solanki@intel.com>
Reviewed-by: Wai-Hong Tam <waihong@google.com>
diff --git a/server/site_tests/firmware_ConsecutiveBoot/firmware_ConsecutiveBoot.py b/server/site_tests/firmware_ConsecutiveBoot/firmware_ConsecutiveBoot.py
index 34774e3..49da5b0 100644
--- a/server/site_tests/firmware_ConsecutiveBoot/firmware_ConsecutiveBoot.py
+++ b/server/site_tests/firmware_ConsecutiveBoot/firmware_ConsecutiveBoot.py
@@ -77,6 +77,14 @@
                 return
         raise ConnectionError()
 
+    def cleanup(self):
+        try:
+            # Restore the GBB flag in developer mode test.
+            self.clear_set_gbb_flags(vboot.GBB_FLAG_DEV_SCREEN_SHORT_DELAY, 0)
+        except Exception as e:
+            logging.error("Caught exception: %s", str(e))
+        super(firmware_ConsecutiveBoot, self).cleanup()
+
     def run_once(self, host, dev_mode=False):
         for i in xrange(self.faft_iterations):
             logging.info('======== Running FAFT ITERATION %d/%s ========',