Base Exception should also be catched here, crashed when ProgrammingError

[piyusql]

https://github.com/vmware/bridgeql/blob/cb3055ac88f352d2531d1e0cd4036e96a4e0d805/bridgeql/django/bridge.py#L50

We have tested a case when DB raised the permission error and it was unable to handle

ProgrammingError: permission denied for table <table_name>

File "py27env/lib/python2.7/site-packages/bridgeql/django/bridge.py", line 50, in read_django_model
qset = mb.queryset()  # get the result based on the given parameters
File "py27env/lib/python2.7/site-packages/bridgeql/django/models.py", line 328, in queryset
return list(self.qset)