Use to_utf8() instead of safe_encode() in convert_str()
Use to_utf8() instead of safe_encode() in convert_str()

safe_encode() convert string using locale [1]. To avoid
possible confuses we should use to_utf8() method instead.

[1] https://wiki.openstack.org/wiki/Python3#safe_encode

Change-Id: I4b8d81bcec389f224084e5270e884e38836d1136

Datera/cinder,NetApp/cinder,j-griffith/cinder,bswartz/cinder,openstack/cinder,openstack/cinder,ge0rgi/cinder,Nexenta/cinder,j-griffith/cinder,cloudbase/cinder,phenoxim/cinder,eharney/cinder,phenoxim/cinder,Hybrid-Cloud/cinder,eharney/cinder,NetApp/cinder,cloudbase/cinder,Datera/cinder,mahak/cinder,Hybrid-Cloud/cinder,mahak/cinder,Nexenta/cinder,bswartz/cinder