Debugged set_info.
Debugged set_info.

Now it fails if the user sends just one scalar for the locations of
label 'all'.


Former-commit-id: 958f0ab6083ade331dd08fc6012dec05980ad30d
Former-commit-id: 99af5c28657a886f7827e287c1a66d0093f20974
stadelmanma/OpenPNM,PMEAL/OpenPNM,amdouglas/OpenPNM,TomTranter/OpenPNM,amdouglas/OpenPNM