Drop bunch of macro definitions needlessly duplicated with rpm
Specifically, the following are gone from here now: %_prefix,
%_sysconfdir, %_infodir, %_mandir, %_defaultdocdir, %_configure,
%makeinstall, %debug_package, %_use_internal_dependency_generator,
%_missing_doc_files_terminate_build, %_unpackaged_files_terminate_build