Remove python-neutronclient requirement

Now that the neutron support is using the openstacksdk
requirement, the python-neutronclient requirement can
be removed.

Change-Id: Ieefac297e136f2f2997ec41cef2673e814c75b55
Related-to: blueprint neutron-client

Author: rtheis

requirements.txt

@@ -16,6 +16,5 @@ python-glanceclient>=0.18.0
 python-keystoneclient!=1.8.0,>=1.6.0
 python-novaclient!=2.33.0,>=2.29.0
 python-cinderclient>=1.3.1
-python-neutronclient>=2.6.0
 requests>=2.8.1
 stevedore>=1.5.0 # Apache-2.0