net-misc/iputils: update 99999999 to match 20160308

net-misc/iputils: update 99999999 to match 20160308

The current `net-misc/iputils-99999999` is no longer working. This
commit switches upstream to `github.com/iputils/iputils` to match
the changes already done in `iputils-20160308.ebuild`.

This patch was created using the following command:

    cp iputils-20160308.ebuild iputils-99999999.ebuild

The following changes happened:

 * Switch upstream to `github.com/iputils/iputils`
 * Add nettle and openssl use flags
 * Remove obsolete patches
 * Adapt `src_configure()` and related functions

More changes will come as separate commits to mark the changes
clearly.