fix for python 2.6.6 (standard version in CentOS 6.6)

error: ValueError('zero length field name in format',)

StackOverflow's link for similar explanation: http://stackoverflow.com/questions/20941386/django-manage-py-returns-valueerror-zero-length-field-name-in-format
Merge pull request #111 from pminakov/develop

fix for python 2.6.6 (standard version in CentOS 6.6)