Sanitize the hardlink test size thing

Sanitize the hardlink test size thing

- The previous "echo $0" got actually expanded to the temporary
  build-time script name, something like /var/tmp/rpm-tmp.UtGhG1,
  which isn't what we're interested in, and depends on rpm
  configuration so can easily cause false positives. Just use
  %{name}-%{version} to get stable content.
(cherry picked from commit 9e918abb4c6d577f3aae2a1a1abd0f4e67f2d151)