bug adding to course by email when email already known.
bug adding to course by email when email already known.

DrXyzzy/smc,DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,sagemathinc/smc