Fixed the -n option with _mingw32_debug_package macro
The -n option was passed down to -debuginfo subpackage's %package and
%description sections, but not to %files. This change fixes %files to
work the %same way as %package and %description.
Not sure yet if the -n option will get any use, but at least this fixes
an obvious oversight.
https://bugzilla.redhat.com/show_bug.cgi?id=700815#c12