USN-4649-2: xdg-utils regression

USN-4649-2: xdg-utils regression

USN-4649-1 fixed vulnerabilities in xdg-utils. That update caused a regression
by removing the –attach functionality in thunderbird and others applications.
This update fix the problem by reverting these changes.

Original advisory details:

Jens Mueller discovered that xdg-utils incorrectly handled certain URI.
An attacker could possibly use this issue to expose sensitive information.
Source: USN-4649-2: xdg-utils regression