Use built-in function setattr() directly
Use built-in function setattr() directly

__builtin__ does not exist in Python 3.
setattr() is built-in function in both python2 and python3.
ref:https://docs.python.org/2/library/functions.html
    https://docs.python.org/3/library/functions.html

Partially implements: blueprint trove-python3
Change-Id: I652b2b82656826944d17fad07ef9dd2e5d228201

redhat-openstack/trove,redhat-openstack/trove,redhat-openstack/trove,openstack/trove,mmasaki/trove,mmasaki/trove,openstack/trove,zhangg/trove,hplustree/trove,hplustree/trove,zhangg/trove,mmasaki/trove