Add more clear codes in ServiceCluster#reset().
Add more clear codes in ServiceCluster#reset().

VM template values and AMQP server reference value have to be cleared before importing cluster.rb as well as other member variables.
otherwise the old template data which is stored in the database will be refered, then launching VMs or the agent in new VM instance
will fail.

axsh/wakame-fuel,axsh/wakame-fuel,axsh/wakame-fuel