Revert "Pin pip to less than version 8 in install_puppet.sh"

This reverts commit fce3e9d93b.

pip 8.0.1 rolled back the breaking change.

From the release notes at: https://pip.pypa.io/en/stable/news/

8.0.1 (2016-01-21)
 Rollback the removal of the ability to uninstall distutils installed
 items until a future date.

Change-Id: I3c9f2ed491689cbdafe10f6115ba3f61a0f03215

install_puppet.sh

@@ -214,7 +214,7 @@ function setup_pip {
         zypper --non-interactive in --force-resolution python python-xml
     fi
 
-    python get-pip.py -c <(echo 'pip<8')
+    python get-pip.py
     rm get-pip.py
     pip install -U setuptools
 }