Avoid RequestURITooLong exception in metadata agent

Length of API port query is proportional to number of networks
and may exceed URI limit. The solution is to query ports by
given ip address only and then filter them by network_id.

Closes bug 1348097

Change-Id: I2a87d6b215df380b24dd5ebb24947e8729f3f6fb
Add definition for new VIF type

The type VIF_TYPE_DVS is added. This indicates that the port
will be added to a VMware distributed virtual switch.

This is for blueprint vsphere-neutron.

Change-Id: I1b5df837734af9a3f7d48b60de120592b11e392e
Set python hash seed to 0 in tox.ini

New tox (>=1.7.0) sets a random python hash seed by default. This is
generally good for testing because it will help keep projects working
regardless of the hash seed, but neutron unittests don't currently pass
with a random hash seed so set it to the python default seed.

This change will allow us to use new tox again and remove the
restriction on tox<=1.6.1 to run unittests.

Note this change will need to be backported to the stable branches to
keep unittests there working with new tox as well.

Change-Id: If151efeb8caae3111515191e238d6e6ae491cd44
Merge "Set python hash seed to 0 in tox.ini"
Merge "Add definition for new VIF type"
Merge "Avoid RequestURITooLong exception in metadata agent"