Tests from test_share_links_search are causing timing issues with QThread

The start method from QThread is not being patched properly and this is causing a race condition because some part of the test is running as a thread.

In one of my computers (Mac, which is slower) i'm getting this:

[FAIL]
Traceback (most recent call last):
  File "/Users/gatox/canonical/build-env/scripts/devsetup/parts/ubuntuone-control-panel/ubuntuone/controlpanel/gui/qt/tests/test_share_links_search.py", line 221, in test_filter
    self.assertEqual(expected, self.ui.temp_u1_files)
  File "/Users/gatox/canonical/build-env/scripts/devsetup/eggs/Twisted-11.1.0-py2.7-macosx-10.4-x86_64.egg/twisted/trial/unittest.py", line 270, in assertEqual
    % (msg, pformat(first), pformat(second)))
twisted.trial.unittest.FailTest: not equal:
a = ['~/blabla/iop']
b = []

ubuntuone.controlpanel.gui.qt.tests.test_share_links_search.SearchBoxTestCase.test_filter
===============================================================================
[FAIL]
Traceback (most recent call last):
  File "/Users/gatox/canonical/build-env/scripts/devsetup/parts/ubuntuone-control-panel/ubuntuone/controlpanel/gui/qt/tests/test_share_links_search.py", line 108, in test_key_down_pressed_load_more_items
    self.assertEqual(self.ui.popup.list_widget.count(), 20)
  File "/Users/gatox/canonical/build-env/scripts/devsetup/eggs/Twisted-11.1.0-py2.7-macosx-10.4-x86_64.egg/twisted/trial/unittest.py", line 270, in assertEqual
    % (msg, pformat(first), pformat(second)))
twisted.trial.unittest.FailTest: not equal:
a = 0
b = 20

ubuntuone.controlpanel.gui.qt.tests.test_share_links_search.SearchBoxTestCase.test_key_down_pressed_load_more_items
===============================================================================
[FAIL]
Traceback (most recent call last):
  File "/Users/gatox/canonical/build-env/scripts/devsetup/parts/ubuntuone-control-panel/ubuntuone/controlpanel/gui/qt/tests/test_share_links_search.py", line 132, in test_key_up_pressed_stay_in_0
    self.assertEqual(self.ui.popup.list_widget.currentRow(), 0)
  File "/Users/gatox/canonical/build-env/scripts/devsetup/eggs/Twisted-11.1.0-py2.7-macosx-10.4-x86_64.egg/twisted/trial/unittest.py", line 270, in assertEqual
    % (msg, pformat(first), pformat(second)))
twisted.trial.unittest.FailTest: not equal:
a = -1
b = 0

ubuntuone.controlpanel.gui.qt.tests.test_share_links_search.SearchBoxTestCase.test_key_up_pressed_stay_in_0
===============================================================================
[FAIL]
Traceback (most recent call last):
  File "/Users/gatox/canonical/build-env/scripts/devsetup/parts/ubuntuone-control-panel/ubuntuone/controlpanel/gui/qt/tests/test_share_links_search.py", line 206, in test_process_volumes_info
    self.assertEqual(self.ui._thread_explore.u1_files, expected)
  File "/Users/gatox/canonical/build-env/scripts/devsetup/eggs/Twisted-11.1.0-py2.7-macosx-10.4-x86_64.egg/twisted/trial/unittest.py", line 270, in assertEqual
    % (msg, pformat(first), pformat(second)))
twisted.trial.unittest.FailTest: not equal:
a = []
b = ['other_path/test/qwe',
 '~/blabla/iop',
 '~/one/file3',
 '~/test/asd',
 '~/ubuntu/file1',
 '~/ubuntu/file2']

ubuntuone.controlpanel.gui.qt.tests.test_share_links_search.SearchBoxTestCase.test_process_volumes_info
===============================================================================
[ERROR]
Traceback (most recent call last):
  File "/Users/gatox/canonical/build-env/scripts/devsetup/parts/ubuntuone-control-panel/ubuntuone/controlpanel/gui/qt/tests/test_share_links_search.py", line 144, in test_key_return_pressed
    self.ui._key_return_pressed(current)
  File "/Users/gatox/canonical/build-env/scripts/devsetup/parts/ubuntuone-control-panel/ubuntuone/controlpanel/gui/qt/share_links_search.py", line 186, in _key_return_pressed
    self._set_selected_item(item)
  File "/Users/gatox/canonical/build-env/scripts/devsetup/parts/ubuntuone-control-panel/ubuntuone/controlpanel/gui/qt/share_links_search.py", line 205, in _set_selected_item
    self.itemSelected.emit(widget.file_path)
exceptions.AttributeError: 'NoneType' object has no attribute 'file_path'

ubuntuone.controlpanel.gui.qt.tests.test_share_links_search.SearchBoxTestCase.test_key_return_pressed
-------------------------------------------------------------------------------
Ran 1254 tests in 83.117s

FAILED (skips=1, failures=4, errors=1, successes=1248)

This is because the start() function of the QThread is executed in the initialization of the object before these method is patched properly.