MMCore: Prevent System-Startup failure in certain cases
MMCore: Prevent System-Startup failure in certain cases

Applying a config preset (such as System-Startup) when the system state
cache has missing properties can fail. Prevent that.

git-svn-id: 03a8048b5ee8463be5048a3801110fb50f378627@16014 d0ab736e-dc22-4aeb-8dc9-08def0aa14fd

kmdouglass/Micro-Manager,kmdouglass/Micro-Manager