rpm fedora: remove fedora related stuff

It's not maintained anymore, so I've removed it.

I've just heard that MariaDB 10.0.15 will be shipped with Mroonga!
It is a good news because MariaDB 10.0.14 is already adopted in Fedora
rawhide, it will be upgraded to 10.0.15 sooner or later.

Thus, we recommends to use it in Fedora 21 or later.