ESUP-Portail phpCAS

In at least version esup-phpcas-0.5.1-1, $PHPCAS_DEBUG['indent'] is getting
clobbered somehow. Although there is a global initializer that should be
assigning $PHPCAS_DEBUG['indent'] to 0, calls to phpCAS::log will often
generate PHP notices that inform us that indent is an undefined index into
the $PHPCAS_DEBUG array.

If we desire to be conservative with PHP notices, we should consider fixing
this issue. This problem doesn't have any serious side-effects that I can
see. As such, this should be a lower priority issue to address.