make add_execution_profile synchronous with pool creation
make add_execution_profile synchronous with pool creation

PYTHON-569

mambocab/python-driver,datastax/python-driver,stef1927/python-driver,mambocab/python-driver,thelastpickle/python-driver,thelastpickle/python-driver,datastax/python-driver,vipjml/python-driver,coldeasy/python-driver,thobbs/python-driver,thobbs/python-driver,vipjml/python-driver,coldeasy/python-driver,stef1927/python-driver