Adds instructions to perform nodes migration
Adds instructions to perform nodes migration

This patch add a section to OneView driver docs with instructions
to migrate nodes from pre-allocaiton model to dynamic allocation
model using Ironic CLI.

Change-Id: I55fb5e3f23e763ca93648bdfbebba6447281717a
Closes-Bug: 1611155
Depends-On: I940904fbbd44b595759883d944a54dd37fac5c35

NaohiroTamura/ironic,openstack/ironic,openstack/ironic,SauloAislan/ironic,pshchelo/ironic,pshchelo/ironic,SauloAislan/ironic,NaohiroTamura/ironic