startup alert, handle case where param returns none

selfdrive/car/car_helpers.py

@@ -10,8 +10,8 @@ from selfdrive.car import gen_empty_fingerprint
 
 def get_startup_alert(car_recognized, controller_available):
   alert = 'startup'
-  if Params().get("GitRemote").decode('utf-8') in ['git@github.com:commaai/openpilot.git', 'https://github.com/commaai/openpilot.git']:
-    if Params().get("GitBranch").decode('utf-8') not in ['devel', 'release2-staging', 'dashcam-staging', 'release2', 'dashcam']:
+  if Params().get("GitRemote", encoding="utf8") in ['git@github.com:commaai/openpilot.git', 'https://github.com/commaai/openpilot.git']:
+    if Params().get("GitBranch", encoding="utf8") not in ['devel', 'release2-staging', 'dashcam-staging', 'release2', 'dashcam']:
       alert = 'startupMaster'
   if not car_recognized:
     alert = 'startupNoCar'