Add unit tests for VolumeRemove
Add unit tests for VolumeRemove

Signed-off-by: Vincent Demeester <87e1f221a672a14a323e57bb65eaea19d3ed3804@sbr.pm>

thaJeztah/engine-api,vdemeester/engine-api,docker/engine-api,jwhonce/engine-api,mikedougherty/engine-api