ENH: Remove try/catch exception handling around dynamic_catch

A call to dynamic_cast will not throw an exception, ever. If
the dynamic_cast fails it returns 0, so it's pointless to put
it in a try/catch block.

Change-Id: Iae0f17504201e6b762cf2a3019abba9c36349325
Merge topic 'RemoveTryCatchForDynamicCast'

28a31e69 ENH: Remove try/catch exception handling around dynamic_catch