python-keystoneclient: Bump to 0.6.0

The 0.6.0 release is fully Python 3 compatible. Requiring at least this version
would help porting the clients that depend on the keystone client.

Change-Id: I3dc0d145f825d92a04f3a7197319f8147adc3913
Update neutron-client minimum to 2.3.4

Closes-bug:1280941
Change-Id: I1de211c0920e629621a64caefc2a639769e32425
Update openstack-doc-tools to 0.7.1

We now need at least version 0.7.1 of openstack-doc-tools.

Change-Id: Ie449294e5e7a7a6758969857c878953718d0320c
Update pecan >= 0.4.5 in global requirements.

Pecan has undergone a variety of bug fixes and performance enhancements,
including fixes that resolve issues in ceilometer.

Change-Id: I6106c34579ee05bc0aa72485795b520a0b370db3
Merge "python-keystoneclient: Bump to 0.6.0"
Merge "Update neutron-client minimum to 2.3.4"
Merge "Update openstack-doc-tools to 0.7.1"
Merge "Update pecan >= 0.4.5 in global requirements."