nrwt is failing to upload test results on the chromium-mac-leopard bots

nrwt is failing to upload test results on the chromium-mac-leopard bots
https://bugs.webkit.org/show_bug.cgi?id=83230

Reviewed by Ojan Vafai.

This should fix things properly; FileUploader() was setting the
socket default timeout value, and apparently that doesn't work
properly with urllib. Also, the class had a bad try/finally
block that was causing the exceptions to be swallowed :(.

* Scripts/webkitpy/common/net/file_uploader.py:
(FileUploader.__init__):
(FileUploader._upload_data.callback):
(FileUploader):
(FileUploader._upload_data):
* Scripts/webkitpy/common/net/networktransaction.py:
(NetworkTimeout.__str__):
(NetworkTransaction.run):
* Scripts/webkitpy/layout_tests/layout_package/json_results_generator.py:
(JSONResultsGeneratorBase.upload_json_files):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@113399 268f45cc-cd09-0410-ab3c-d52691b4dbfc