Fix destination_type attribute in the bdm_v2 documentation
Fix destination_type attribute in the bdm_v2 documentation

All the clients using block device mapping are using the attribute
destination_type and the documentation points to dest_type instead.

Change-Id: Iba6e698e826d1a1898fde5cc999592f5821e3ebc
Co-Authored-By: David Moreno Garcia <85283a3a0d1545d3f179ecdf5d020d82b27d82aa@gmail.com>
Closes-Bug: #1808358

openstack/nova,klmitch/nova,mikalstill/nova,rahulunair/nova,mikalstill/nova,mahak/nova,rahulunair/nova,klmitch/nova,klmitch/nova,mahak/nova,rahulunair/nova,mahak/nova,klmitch/nova,openstack/nova,openstack/nova,mikalstill/nova