No unit test for multiline notifications

[Michał Sawicz]

Bug #1504256 got through the cracks, meaning we don't have a unit test for that case.

We should test if \n fed to the notification result in the expected lineCount in the notification.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: unity8 8.11+15.10.20150930.1-0ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-14.16-generic 4.2.2
Uname: Linux 4.2.0-14-generic x86_64
ApportVersion: 2.19.1-0ubuntu2
Architecture: amd64
CurrentDesktop: Unity
Date: Fri Oct 9 15:22:01 2015
SourcePackage: unity8
UpgradeStatus: No upgrade log present (probably fresh install)