ensure dispatcher service is configured before rpc

there is a rare race condition where when the mq contains
notifications, the rpc service is configured before dispatcher so
it may attempt to start sending messages to dispatcher before it
has been configured. this patch ensures the dispatcher
configuration is done before starting rpc service.

Closes-Bug: #1384364

Change-Id: If4c3a225e0bd5ae6eefad072b844af1ef5786f3f
(cherry picked from commit 5df14763a5a88b9549066da04dac13ae2ad73144)
Merge "ensure dispatcher service is configured before rpc" into stable/icehouse