Indent code with TABs

Indent code with TABs

We indent with TABs and sometimes for fine alignment, TABs followed by
spaces, but never all spaces (unless the indentation is less than 8
columns). Indenting with spaces slips through in some places. Fix
them.

Imported code and compat/ are left alone on purpose. The former should
remain as close as upstream as possible. The latter pretty much has
separate maintainers, it's up to them to decide.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>