Hi,
your package is still using the old %ruby_sitelib and %ruby_sitearch macros,
which are now replaced by %ruby_vendorlibdir and %ruby_vendorarchdir. These are
located in macros.ruby in ruby-devel package (therefore you don't need to
define them). The old macros now point to /usr/local, which results in an
unwanted placement of files in your package under /usr/local.