Document that Tails Installer cannot be read by Orca on Wheezy

Reported by user, confirmed by me:

Opening Orca before and all, Tails installer cannot be read by Orca

Steps to reproduce:

- Open Orca
- Open Tails installer

Error:

Orca says the name of the app and ‘Unaccesible’

Feature Branch: bug/9739-tails_installer_orca

Original created by @emmapeel on 9739 (Redmine)

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