Shorter default lock wait for vehicle_locations

nextbus.py

@@ -366,13 +366,15 @@ class Nextbus():
             return predictions
 
     @classmethod
-    def get_vehicle_locations(cls, agency_tags, truncate=True):
+    def get_vehicle_locations(cls, agency_tags, truncate=True, max_wait=10):
         """
         Get vehicle GPS locations
         """
         if not agency_tags:
             return []
-        with Lock("agencies", shared=True), Lock("routes", shared=True), Lock("vehicle_locations"):
+        with Lock("agencies", shared=True, timeout=max_wait),\
+             Lock("routes", shared=True, timeout=max_wait),\
+             Lock("vehicle_locations", timeout=max_wait):
             db.session.begin()
             routes = db.session.query(Route).join(Agency)\
                 .options(joinedload('directions'))\