Fixes EUCA-4696 Use --bootstrap-host for GMS

To use the eucalyptus-cloud without multicast provide each java
host as an entry in eucalyptus.conf:CLOUD_OPTS on each java host.

This will use TCPGOSSIP instead of multicast.  Note that the
failure detection behaviour will be subtly different, especially
around handling of hard host failures/reboots (triggering TCP MSS).