In Python 3, the variable with the currently handled exception is unset
at the end of the except block. (This is done to break reference
cycles, since exception instances now carry tracebacks, which contain
all locals.)
Fix this in baseldap's error handler.
Use a simpler structure for the ipatests.raises utility that only uses the
exception inside the except block.
Reviewed-By: Tomas Babej <tbabej@redhat.com>