[Debian-on-mobile-maintainers] Bug#1052401: plasma-mobile: correction to short description

[Ben Tris]

No need to follow the original description.
It's not uncommon that a package is open source in Debian main.
Do not expect that it's the only open source in it's kind.

Debian policy
3.4.1 The single line synopsis
developers reference
6.2.2 The package synopsis, or short description