Use latest build infrastructure.

Version caps on pip/pbr/wheel/setuptools are a disconnect between
the incubator and upstream infra tooling which updates everything
everytime. Since we can't do sensible deps on them (due to
setup_requires behaviour), we need to update them in advance.

Change-Id: Iaeaf5affd55e6b6ea98dc65fb64b997aa6565f6d

scripts/setup-clienttools

@@ -14,13 +14,9 @@ set +u
 source $VENV_HOME/bin/activate
 set -u
 
-# Need setuptools>=1.0 to manage connections when
-# downloading from pypi using http_proxy and https_proxy
-pip install -U 'setuptools>=1.0'
-
-# bug #1293812 : Avoid easy_install triggering on pbr as easy_install is
-# fragile.
-pip install -U 'pbr>=0.5.21,<1.0'
+# Use latest versions of build/environment tooling.
+pip install -U pip
+pip install -U wheel setuptools pbr
 
 pip install -U \
     os-apply-config \