Removing the subnets from shared networks

RM8483

Created regression in the test_networks suite. Can only test 'getting' a
shared net here. It isn't possible, without modifications to the mock, to test
'not getting' a shared net. I considered modifying the mock but then all these
tests would pretty much be testing my new mock instead of actual things.

All this is supposed to do is ensure that, if a network is shared, the subnets
are not included in the output.

Updated the not shared check to ensure correctness.
Merge pull request #194 from roaet/remove_subnets_from_shared_networks

Removing the subnets from shared networks