Protect against null exception handler start.
Protect against null exception handler start.

fnajera-rac-de/cecil,jbevain/cecil,joj/cecil,cgourlay/cecil,saynomoo/cecil,sailro/cecil,SiliconStudio/Mono.Cecil,xen2/cecil,furesoft/cecil,ttRevan/cecil,kzu/cecil,mono/cecil,gluck/cecil