OM_DVGEOCOMP's update_jac may not be defined on hot start

[bmlowe4]

https://github.com/mdolab/pygeo/blob/e2cdcbd567d4ebe4f22f64281a23da4dc0fa7a3c/pygeo/mphys/mphys_dvgeo.py#L1012

When running a hot start through openMDAO/MPhys, it may be possible that OM_DVGEOCOMP's compute_jacvec_product() is called before compute(), in which case the boolean update_jac isn't defined yet.

[A-CGray]

Sorry @bmlowe4 , I hadn't seen your issue previously. I coincidentally ran into the same error (although not via a hot-start) today and pushed a fix in https://github.com/mdolab/pygeo/pull/279