Coverage data collection is broken

[Mauko Quiroga-Alvarado]

Hi there!

I really enjoy OpenFisca, but I recently encountered an issue.

Here is what I did:

make test-core

Here is what I expected to happen:

Coverage to be 75%

Here is what actually happened:

Coverage is 54%

Here is data (or links to it) that can help you reproduce this issue:

#1073