fix: Set permissions to traverse all OS image dirs
fix: Set permissions to traverse all OS image dirs

The OS distro install files in the '/var/www/html' directory are made
available over http. All subdirectories need to have their execute mode
bit set.

Change-Id: I477a364279180abdd44c1b317e6dc1ff86d43e4d

open-power-ref-design-toolkit/cluster-genesis,open-power-ref-design-toolkit/cluster-genesis