[Fedora-packaging] Remove requirement to use macros for paths

[Toshio Kuratomi]

Recently the question of why we require people to macroize their paths in
spec files (and by extension, patch build scripts to use the expansion of
our macros instead of hardcoded values) came up.  FPC only knew of one, not
so great reason: if the paths were to change, for instance a change in the
FHS, then spec files that use macros (in both the spec file and the
expansion of those macros is used in the upstream build scripts) would only
need a rebuild to pick up th new paths.

I then opened this ticket:  https://fedorahosted.org/fpc/ticket/67
for FPC to consider dropping using the directories as a requirement.

As recorded in the comments, some people have stepped forward with the
additional rationale that third-parties rebuilding our packages may wish to
install their rebuilds into a separate directory structure for their own
tracking purposes.  Having directory paths in macros allow them to do that
by redefining %{_prefix}, %{_sharedstatedir}, and a handful of other
toplevel directory macros.  If we allowed hardcoding of directories, then
they'd have to edit the spec file to achieve the same goal.

If people have additional reasons that macroizing all directory paths make
sense, please let us know (here or as a comment in the ticket).  Then FPC
can decide whether to relax this rule or update the rule with information
about why we have it in place.

Thanks,
-Toshio