fix render time reporting
fix render time reporting

We were using an uninitialized value to calculate this figure.

jcfr/CDash,cpatrick/CDash,jcfr/CDash,cpatrick/CDash,jcfr/CDash,cpatrick/CDash,cpatrick/CDash,cpatrick/CDash,jcfr/CDash,cpatrick/CDash,jcfr/CDash,jcfr/CDash