removed extra exception for check_model in inference/base.py
removed extra exception for check_model in inference/base.py

khalibartan/pgmpy,kris-singh/pgmpy,jhonatanoliveira/pgmpy,sandeepkrjha/pgmpy,abinashpanda/pgmpy,kris-singh/pgmpy,pgmpy/pgmpy,sandeepkrjha/pgmpy,anaviltripathi/pgmpy,abinashpanda/pgmpy,liquidmetal/pgmpy,ankurankan/pgmpy,liquidmetal/pgmpy,khalibartan/pgmpy,anaviltripathi/pgmpy,jhonatanoliveira/pgmpy,ankurankan/pgmpy,pgmpy/pgmpy