[rubygem-narray/f19] Fedora <= 18 && RHEL <= 6 need Requires: ruby(abi)

[Björn 'besser82' Esser]

Summary of changes:

  406479c... Fedora <= 18 && RHEL <= 6 need Requires: ruby(abi) (*)

(*) This commit already existed in another branch; no separate mail sent