Remove ExoGENI signer cert.
Remove ExoGENI signer cert.

The expired ExoGENI signer cert causes Flack SSL failures, so delete
it until a new signer is available.

charliemeyer/geni-portal,charliemeyer/geni-portal,tcmitchell/geni-portal,tcmitchell/geni-portal,tcmitchell/geni-portal,tcmitchell/geni-portal,charliemeyer/geni-portal,charliemeyer/geni-portal,charliemeyer/geni-portal,tcmitchell/geni-portal