Homeassistant: Set permissions before install.

[ludeeus]

Description:

The install_homeassistant.service now upgrades hassbian-scripts on first boot if there is an update, resulting in /srv/homeassistant being owned by root.

From first boot:

pi@hassbian:~ $ ls -ld /srv/homeassistant
drwxr-xr-x 3 root root 4096 Nov 12 22:11 /srv/homeassistant

And in journalctl

Nov 12 22:11:30 hassbian hassbian-config[1223]: Changing to the homeassistant user
Nov 12 22:11:30 hassbian hassbian-config[1223]: Creating Home Assistant venv
Nov 12 22:11:31 hassbian hassbian-config[1223]: Error: [Errno 13] Permission denied: '/srv/homeassistant/include'
Nov 12 22:11:31 hassbian hassbian-config[1223]: Changing to Home Assistant venv
Nov 12 22:11:31 hassbian hassbian-config[1223]: /bin/bash: line 6: /srv/homeassistant/bin/activate: No such file or directory

By explicit setting permissions before the install starts this will be corrected.
Added it to the upgrade script to for good measure.

Checklist (Required):

• The code change is tested and works locally.
• The code is compliant with Contributing guidelines

[ludeeus]

This should be released as a hotfix for 0.11.1 as soon as possible since all new installs now fail.