In order to support Infiniband network, the bootstrap image
is changed when installing Mellanox plugin in Fuel 6.1.
The replacement is done in the post installation section of Mellanox
Plugin RPM.
The new bootstrap files and a script to reboot the discovered nodes with
the old bootstrap, are added to the plugin.
Partially-implements: blueprint support-infiniband-network
Change-Id: I092677a69bc3a3ad5db068d91252ba69f46ea400