Use built-in RPM dependency generator in all packages

ocaml-camomile.spec, ocaml-libvirt.spec, ocaml-ounit.spec and ocaml-text.spec turn off RPM's built in dependency generation:

> %define _use_internal_dependency_generator 0 
> %define __find_requires /usr/lib/rpm/ocaml-find-requires.sh
> %define __find_provides /usr/lib/rpm/ocaml-find-provides.sh 

This doesn't cause problems building in mock on Fedora, but does seem to cause dependency problems when building without it on CentOS.

The ocaml-find-requires.sh and ocaml-find-provides.sh scripts seem quite old and it looks like they are no longer needed with modern versions of RPM.   Is there any reason to use them in these four spec files?