BUG-865: removed unnecessary test file.

Removed ietf-inet-types yang model which is needless for testing groupings.

Signed-off-by: Martin Vitez <mvitez@cisco.com>
(cherry picked from commit 1c39cb5c3ed481946ec9511719a6db3a627536ce)
Signed-off-by: Robert Varga <rovarga@cisco.com>