Correct unresolved ugettext_lazy error strings in git_export command
Merge pull request #5910 from mitocw/cg/git_export_error_output

Correct unresolved ugettext_lazy error strings in git_export command
Fix PEP8: E201 whitespace after '{'
Fix PEP8: E202 whitespace before '}'
Fix PEP8: E203 whitespace before ':'
Fix PEP8: E211 whitespace before '('
Fix PEP8: E221 multiple spaces before operator
Fix PEP8: E222 multiple spaces after operator
Fix PEP8: E225 missing whitespace around operator
Fix PEP8: E226 missing whitespace around arithmetic operator
Fix PEP8: E231 missing whitespace after '[:,]'
Fix PEP8: E241 multiple spaces after ','
Fix PEP8: E251 unexpected spaces around keyword / parameter equals
Fix PEP8: E261 at least two spaces before inline comment
Fix PEP8: W291 trailing whitespace
Lower PEP8 threshold to 150 violations