dbus timeout break activity startup

[godiard]

In activities configured to use a single process (-s parameter in the exec field in the activity.info file), like Browse, Calculate, Chart or Log, at times the activity don't start, and the log show:

1398917197.176818 ERROR dbus.proxies: Introspect error on :1.34:/org/laptop/WebActivity: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: Message did not receive a reply (timeout by message bus)
1398917197.177320 DEBUG dbus.proxies: Executing introspect queue due to error
1398917197.178083 ERROR dbus.connection: Unable to set arguments ({'activity_id': '71f16515964b9e187ba44b39a57fd57ab63f532b', 'invited': False, 'object_id': 'ef21932a-6a30-4a24-b001-61d5ab095084'},) according to signature None: <type 'exceptions.TypeError'>: Expected a string or unicode object
Traceback (most recent call last):
  File "/usr/bin/sugar-activity", line 164, in <module>
    main()
  File "/usr/bin/sugar-activity", line 151, in main
    dbus_interface='org.laptop.SingleProcess')
  File "/usr/lib/python2.7/site-packages/dbus/proxies.py", line 70, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib/python2.7/site-packages/dbus/proxies.py", line 145, in __call__
    **keywords)
  File "/usr/lib/python2.7/site-packages/dbus/connection.py", line 641, in call_blocking
    message.append(signature=signature, *args)
TypeError: Expected a string or unicode object
1398917198.173304 DEBUG root: _cleanup_temp_files
Exited with status 1, pid 1285 data (None, <open file '<fdopen>', mode 'w' at 0xf78de0>, dbus.ByteArray('71f16515964b9e187ba44b39a57fd57ab63f532b', variant_level=1))

This issue was reported in AU (​https://olpcau.atlassian.net/browse/AD-39)

Steps to reproduce the test scenario:

1. Install a 0.100 image like 33032xx4 or 33034xx4 on Xo-4.
2. Boot, and connect it to wifi network with internet enabled
3. Start the Browse activity, Open some website
4. Close the Browse Activity
5. Start the Browse Activity immediately (Repeat step 3-5 until you observe the Error "Browse Failed to start" )

[Gonzalo Odiard]

Avoid breaking activity startup by dbus timeout on sigle instance - Fixes #4773

This problem only happen in activities configured with the option -s
in the activity.info "exec" field, and the objective is use a single process,
even when starting more than one instance. If the process do not reply,
start a new process, instead of show a error.

Signed-off-by: Gonzalo Odiard <godiard@…>

Changeset: f157b1148edd81c914a1bdcfbc6f91b6727f9191