packaging: fix spec file problems found by rpmlint

Fixes the following rpmlint warnings:

- W: mixed-use-of-spaces-and-tabs
The specfile mixes use of spaces and tabs for indentation, which is a
cosmetic annoyance.  Use either spaces or tabs for indentation, not
both.

- pcp.src: W: invalid-url Source1: pcp-webjs.src.tar.gz
The value should be a valid, public HTTP, HTTPS, or FTP URL.
packaging: fix compat tmpdir renaming holes in debian postinst
packaging: add note re debian bugs fixed this release