Raise eventlet to 0.13.0

eventlet 0.13.0 provides the python 3.x compatible
timeout parameter in subprocess module
(https://bitbucket.org/eventlet/eventlet/issue/89)

Change-Id: I712cecc7fe2f136fe985f2adc34acc570df52547
Add pysnmp needed for Ceilometer/HardwareAgent/SNMPInspector

The actual PySNMP version runs with Python 2.4 through 3.3
For more information about PySNMP see http://pysnmp.sourceforge.net/
Changelog: http://pysnmp.sourceforge.net/changes.html

Change-Id: I29986f7ca96079b4cbc1d7d96f9abe2bfc3c9d5f
Update keyring minimum version

The keyring author has released an update that no longer
includes ptr in the setup_requires unless the command
being run is 'python setup.py ptr'. Let's use that version
to get around the weird dependency issue we have.

https://bitbucket.org/kang/python-keyring-lib/issue/105/pytest-runner-should-be-in-test
https://bitbucket.org/kang/python-keyring-lib/commits/29116566d46e

Change-Id: I0ea61e1bb264b9ed8b141332434672bb2b521e13
Raise psutil requirement

Psutil API need use new 'require' condition for users to get network information.

Raise psutil requirement to >=0.6.1,<1.0

Change-Id: I29ef41a59138dfa4dfd0c666c5013c979e17a2ad
remove netifaces as a requirement

Neutron has dropped netifaces in this merge
(https://review.openstack.org/#/c/38257/).

Change-Id: Ifce6c3010924180c174a5bae7d59fe02d5b8ac04