svn-fe: conform to pep8

Quite a large change, most of this was whitespace changes, though there
were a few places where I removed a comma or added a few characters.
Should pass through pep8 and pass every test.

Signed-off-by: William Giokas <1007380@gmail.com>
Acked-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>