Adds IVS unit tests for new VIF firewall logic

Adds new unit tests for the IVS VIF driver to
cover the various possible plugging behaviors
added by the vif_details based logic introduced
in change I3bbcfc67036ab7389c82720add0bc0fc627bfee0.

Closes-Bug: #1301087
Change-Id: I7f0a1460b948a852c2d61d24217bbf27a4d85859
Don't store duplicate policies for server_group

It doesn't make sense to store same policies in a server_group.
We need to deny this usage in server_group creation.

Change-Id: I4f3ad544aef78cbbc076c7a47cca04832a2f5b4b
Closes-Bug: #1324348
Set reasonable defaults for new network values

Partially-implements blueprint better-support-for-multiple-networks

Change-Id: Ic9c60071480abc5fced04dab5fc79ea44db1e10d
Determine shared ip from table instead of flag

Partially-implements blueprint better-support-for-multiple-networks

Change-Id: Id7c6620704fef504d23cb42c5218251fa9e2dba7
Don't follow HTTP_PROXY when talking to localhost test server

Unlike urllib2, requests honours HTTP_PROXY by default.  This meant
test_uri_length_limit's test queries to http://localhost:$port/ would
hit the wrong localhost when $HTTP_PROXY was another host - resulting in a
meaningless test scenario and apparent failures with HTTP status codes
other than the expected REQUEST_URI_TOO_LARGE (414).

This change forces requests to go direct for those test queries.

Closes-Bug: #1329614
Change-Id: Ida3424ca9a750bd2d3f2e81dc7dfacc2a334adf1
Merge "Don't store duplicate policies for server_group"
Merge "Adds IVS unit tests for new VIF firewall logic"
Merge "Set reasonable defaults for new network values"
Merge "Determine shared ip from table instead of flag"
Merge "Don't follow HTTP_PROXY when talking to localhost test server"