add connect_timeout inside set_keyspace_blocking

`set_keyspace_blocking` is called from places holding
a lock, and in case that the connection is closed from
the server side, it might hang forever.

using the `connect_timeout` on it to make sure it
won't hang forever.

Ref: https://github.com/scylladb/scylladb/issues/15661

cassandra/connection.py

@@ -1509,7 +1509,7 @@ def set_keyspace_blocking(self, keyspace):
         query = QueryMessage(query='USE "%s"' % (keyspace,),
                              consistency_level=ConsistencyLevel.ONE)
         try:
-            result = self.wait_for_response(query)
+            result = self.wait_for_response(query, timeout=self.connect_timeout)
         except InvalidRequestException as ire:
             # the keyspace probably doesn't exist
             raise ire.to_exception()