set coffee cache dir, since otherwise Docker image is broken
set coffee cache dir, since otherwise Docker image is broken

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