templates: Remove unused version comparison functions

templates: Remove unused version comparison functions

There are no users left of version_find_latest(), version_test_gt(), and
version_test_numeric(). Remove those unused helper functions. Using
those helper functions is what caused the quadratic sorting performance
issues in the first place, so removing them is a net win.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Robbie Harwood <rharwood@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>