git-p4: add blank lines between functions and class definitions

git-p4: add blank lines between functions and class definitions

In the PEP8 style guidelines, top-level functions and class definitions
should be separated by two blank lines. Methods should be surrounded by
a single blank line.

This guideline is described here in the "Blank Lines" section:
https://www.python.org/dev/peps/pep-0008/#blank-lines

Signed-off-by: Joel Holdsworth <jholdsworth@nvidia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>