[#2264] Add support for Ubuntu 14.04.

Problem?
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2014 is here and 2010 is so far away… :)


Solution?
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Imported the needed changes in `paver.sh` from the corresponding pull request in `python-package`: https://github.com/chevah/python-package/pull/4


How to test?
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Build and test `python-package` as described in the included README.

reviewer: @adiroiban