[DRE-maint] Bug#751386: Rename ruby-hiera to hiera

[Net Kgk]

Package: ruby-hiera
Version: 1.3.0-1

Different name causes dependency
problems when puppetlabs official repository is attached.

For example, I use the Puppetlabs repository only for puppetdb (this
one is missing in Debian repo), and Debian repo for the rest.
Apparently, Puppetlabs development cycle is not synchronized with
Debian, so it is often happens that puppet-master is newer in one
repository or another. But different hiera's package name produces
dependency problems.

In my opinion, it should be called hiera, as it is also a tool, not
only the library. Besides, this is a choice of Puppetlabs itself.

 I am using Debian GNU/Linux Jessie, kernel 3.14-1-amd64 and libc6 2.19-1