Roll back transaction if execution of proc fails

This change to the code the executes stored procedures should abort the transaction if execution of a stored procedure fails.  I need to figure out how to test this, since it will affect all of AG and *not* just the labadmin site...
Weird! That seems to contradict the documentation directly. I'll just remove the else and put the return outside the try.  I guess they're not counting the else as part of the try or something...