Fix command dispatching

DispatchCommand is supposed to be nested:

  ssh server gitblit version --verbose --format json

means that first the command that is seen by dispatching process is
"gitblit". Dispatch command look in its commands map for this command
and dispatch the rest of the command and options and arguments to this
command, version in this example.

Change-Id: I8ef8e0e369922c793ca7ad36c1a8f76b0206baa7