PocoAbstractDao: handle bad_cast when creating session()
PocoAbstractDao: handle bad_cast when creating session()

When a wrong TransactionManager is set and some Dao derived from
PocoAbstractDao asks for a session then bad_cast exception is
thrown. However, it does not contain any useful information and
makes searching the source of the issue diffcult. Convert the
bad_cast to a Poco Exception with a more sensible message.

Signed-off-by: Jan Viktorin <3eab6ac54c005c4408f608556a6663b7f2abede7@fit.vutbr.cz>

BeeeOn/server,BeeeOn/server,BeeeOn/server,BeeeOn/server