[rpm] Requiring python2-devel for BuildRequires

This is so that we focus on Python2 (and not Python3), but also is a better
requirement for building than merely "python".

Thanks to Orion Poplawski from Fedora.
[rpm] Correcting the FSF address

... at least this is the version copied from the gnu.org web page, but
doesn't differ that much from what I had in the file (by maybe a comma and
some spaces).

Thanks to Orion Poplawski from Fedora.
[rpm] Using the GPLv2 text directly downloaded from gnu.org
[rpm] Version numbers in changelog match program version number

Thanks to Orion Poplawski from Fedora.
[rpm] dropping BuildRoot

this is from the advice of Orion Poplawski (Fedora).  It seems that this is
only required if one wants to target EPEL 5
[rpm] commenting %clean out with extra % in changelog

This change advised by Orion Poplawski (Fedora)