packaging: Adjust jami-daemon.spec to use libexec.

This follows commit 2afa99fd1 in the daemon.

* build.py (run_run) <dring>: Adjust file name.
* packaging/rules/rpm/jami-daemon.spec (%install): Likewise.  Hard
code the jamid binary location as /usr/libexec/dring, to not argue
with OpenSUSE Leap's %{_libexecdir}.

Change-Id: Iea6bf3cc6c4dce853f0b7c92861dfee7b8a07bbe