Move negative action tests to right place

Negative tests of server should be written on test_servers_negative.py,
but some negative tests are written on positive tests file, then that
would mislead developers who add new negative tests.

This patch moves these negative tests to a right place.

Change-Id: If3ddb2a0a5d27a87d610c6d8e7783d400fd32606
Skip negative compute quota tests that don't work with Neutron

Change I5187a109f0bacb1f3afa4276b3d73f47fd53ad87 re-enabled some
negative quota tests for compute but they don't work if you're using
Neutron due to nova bug 1186354.

There is a patch up for the bug here:

https://review.openstack.org/#/c/43822/

but it's taking awhile to land so we should skip the tests until that's
working.

Partial-Bug: #1186354

Change-Id: I0458f8cf95585962638a82da34397071e34a1940
Separate negative tests  api/network/security_groups

moved negative tests cases to a new file

Change-Id: I24438d556231d80b21e033acc79da3a050bf31cb
VPNaas vpnservice test cases

Adding testcases for vpn service create, list, delete, and show
part of blueprint: vpnaas-api-test-cases
Change-Id: I015fd503a198f93bfc7382e30b2aff5c74b3fd30
Merge "Skip negative compute quota tests that don't work with Neutron"
Merge "Move negative action tests to right place"
Merge "VPNaas vpnservice test cases"
Merge "Separate negative tests  api/network/security_groups"