Remove requirements that should be a part of the venv definition.

requirements/edx/pre.txt

@@ -4,6 +4,4 @@
 #   * @edx/ospr - to check licensing
 #   * @edx/devops - to check system requirements
 
-# Packaging pre-requisites.
-setuptools==37.0.0
-pip==9.0.1
+# Empty file left here until all the places that expect it have been updated.