[cli] keeping 'copr mock-config' functionality
    
    No doubts, this functionality is needed and there's no real
    technical reason to deprecate this, I already offered a help to
    solve this.
    
    There were refused theories that we'll implement this
    functionality in 'copr-rpmbuild', but that's not viable option
    since copr-rpmbuild is not wanted on EPEL7 (see PR#306), nor even
    on EPEL6.
    
    This reverts commit a42861a1150e3467d4347f0f67128b994cad1def.