After upgrading to glibc-2.2.3-19.1, the file
/usr/lib/gconv/gconv-modules.cache exists but is not owned by any package.
I suspect that it comes from something inside glibc, so glibc needs to ship
an empty copy of it as a config file so that it will own the file.
glibc-2.2.4-1 owns this already.
Fix confirmed in glibc-2.3.2-101.4.