app/dynamic_node_id: don't assume single-threading

Let SQLite verify that for us instead of silently corrupting itself.

dronecan/app/dynamic_node_id.py

@@ -29,8 +29,7 @@ class CentralizedServer(object):
 
     class AllocationTable(object):
         def __init__(self, path):
-            # Disabling same thread check on the assumption that the developer knows what they are doing.
-            self.db = sqlite3.connect(path, check_same_thread=False)  # @UndefinedVariable
+            self.db = sqlite3.connect(path)  # @UndefinedVariable
 
             self._modify('''CREATE TABLE IF NOT EXISTS `allocation` (
             `node_id`   INTEGER NOT NULL UNIQUE,