Disable creating (large) backup files of all requests by default.

Python/vlbi.py

@@ -22,7 +22,7 @@ class ServerError(Exception):
 class Client(object):
     headers = {'content-type': 'application/json'}
 
-    def __init__(self, server, facility, username, password, backup=True, backupDir="./backup"):
+    def __init__(self, server, facility, username, password, backup=False, backupDir="./backup"):
         self.server = server
         self.facility = facility
         self.username = username