MCOP-309 cope with no response

The previous implementation of find_applying_nodes would assume
that a node had completed if they didn't respond to the puppet.status
action as the code was oriented around processing the results set
rather then the expected set of responses.

With this commit we change method to operate in terms of the hosts
we expected to hear from, and count the number of times we didn't
receive a response to the status action.  If we're unresponded to
we increment the :no_response, and on exceeding the threshold we
assume that host is not coming back.
maint - make 5 checks as expected

The test descriptions expect we should check 5 times and no more, the tests
themselves make 6 attempts.  Resolve in favour of the test descriptions.
Merge pull request #39 from richardc/MCOP-309-forgets_nonresponding_nodes

MCOP-309 cope with non-responding nodes