buzilla2trac: fix datetime to epoch conversion which was done in a non-portable way.
buzilla2trac: fix datetime to epoch conversion which was done in a non-portable way.

Thanks to xenolinguist for the patch. Should fix #6794.

git-svn-id: eda3d06fcef731589ace1b284159cead3416df9b@6501 af82e41b-90c4-0310-8c96-b1721e28e2e2

walty8/trac,jun66j5/trac-ja,walty8/trac,jun66j5/trac-ja,netjunki/trac-Pygit2,jun66j5/trac-ja,netjunki/trac-Pygit2,walty8/trac,netjunki/trac-Pygit2,walty8/trac,jun66j5/trac-ja