Fixes issue  #65 "better error when missing or wrong certificate in sp metadata", recgnize that a certificate may not have been set and let SSP generate the error for us.
Fixes issue  #65 "better error when missing or wrong certificate in sp metadata", recgnize that a certificate may not have been set and let SSP generate the error for us.

remold/OpenConext-engineblock,thijskh/OpenConext-engineblock,remold/OpenConext-engineblock,rjkip/OpenConext-engineblock,remold/OpenConext-engineblock,Martin1982/OpenConext-engineblock,Martin1982/OpenConext-engineblock,rjkip/OpenConext-engineblock,rjkip/OpenConext-engineblock,Martin1982/OpenConext-engineblock,Martin1982/OpenConext-engineblock,remold/OpenConext-engineblock,thijskh/OpenConext-engineblock,thijskh/OpenConext-engineblock,rjkip/OpenConext-engineblock,thijskh/OpenConext-engineblock