Fix DBusException using Moon activity

Moon activity makes multiple datastore API calls within one second, and
the file used to store the data is named by the second of the epoch,
such that one API call clashes with another.

Use a sequence number instead of the second of the epoch.

Author: quozl

src/jarabe/apisocket.py

@@ -16,7 +16,6 @@
 import json
 import os
 import struct
-import time
 import binascii
 
 import dbus
@@ -115,12 +114,14 @@ def __init__(self, client):
                                     "/org/laptop/sugar/DataStore")
         self._data_store = dbus.Interface(bus_object,
                                           "org.laptop.sugar.DataStore")
+        self._sequence = 0
 
     def _create_file(self):
         activity_root = env.get_profile_path(self._activity.get_type())
         instance_path = os.path.join(activity_root, "instance")
 
-        file_path = os.path.join(instance_path, "%i" % time.time())
+        self._sequence += 1
+        file_path = os.path.join(instance_path, "%d" % self._sequence)
         file_object = open(file_path, "w")
 
         return file_path, file_object