permission denied on creating alien cache gives misleading error message

A permission denied on creating an alien cache results in a misleading error message in /var/log/messages:
Oct 15 11:53:26 fermicloud350 cvmfs2: (nova.fnaldata.gov) Failed to setup cache in /var/lib/cvmfs/nova.fnaldata.gov: Permission denied (9 - cache directory problem)
when the alien cache is somewhere else.