Move the dependency on Class::ISA to emulab-boss and not p5-RPC-Async.
Move the dependency on Class::ISA to emulab-boss and not p5-RPC-Async.

It is really a dependency on the version of perl installed.
(cherry picked from commit 544f16c16de80f93f19c3f2e9cc4e0d3d43665e4)

nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome