Firstboot script modifications

* Since first-boot.d is already deprecated in DIB proposed
  to remove of its usage from savanna-image-elements
  https://bugs.launchpad.net/diskimage-builder/+bug/1212080
* Use rc.local directly instead of 'first-boot' scripts
* Added chown to ubuntu user for /etc/hadoop dir

NOTE: Such replacemnt is temporary and most likely we need to add os-refresh-config element from
https://github.com/openstack/tripleo-image-elements/tree/master/elements/os-refresh-config as a replacement of first-boot.d

Co-Authored-By: Ivan Berezovskiy <iberezovskiy@mirantis.com>

Change-Id: Ic936be236a0604b1af72cb5553f435cb67f34ece
Merge "Firstboot script modifications"