This mimics behavior of core 'template' module to allow relative
includes from the same dir as merged template, base dir of
playbook/role (usually role for us) and its 'templates' subdir.

Additionally old unused code was removed.

Change-Id: I83804d3cf5f17eb2302a2dfe49229c6277b1e25f
Signed-off-by: Radosław Piliszek <radoslaw.piliszek@gmail.com>