Move pypi to dib-python

The latest Fedora/Ubuntu images don't ship python2 by default, so we
need to use our dib-python wrapper for this so we work in python3 only
environments.

This change also correctly creates the pip.conf and .pydistutils.cfg
files with trusted host extracted from the index-url.

Related-bug: 1577105

Change-Id: Ibb5348af3e3bbe46b19affe90a8930a4b4ad4cad
Signed-off-by: Maksim Malchuk <maksim.malchuk@gmail.com>

diskimage_builder/elements/pypi/element-deps

@@ -0,0 +1 @@
+dib-python

diskimage_builder/elements/pypi/pre-install.d/04-configure-pypi-mirror

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/local/bin/dib-python
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
 # not use this file except in compliance with the License. You may obtain
@@ -16,6 +16,11 @@ from __future__ import print_function
 
 import os.path
 
+try:
+    from urllib.parse import urlparse
+except ImportError:
+    from urlparse import urlparse
+
 
 def main():
     home = os.path.expanduser("~")
@@ -49,6 +54,7 @@ def main():
         output.write('[global]\n')
         output.write('log = %s/pip.log\n' % (home,))
         output.write('index-url = %s\n' % (indices[0],))
+        output.write('trusted-host =  %s\n' % (urlparse(indices[0]).hostname,))
         if retries is not None:
             output.write('retries = %s\n' % retries)
         for index in indices[1:]:
@@ -56,6 +62,7 @@ def main():
     with open(home + '/.pydistutils.cfg', 'wt') as output:
         output.write('[easy_install]\n')
         output.write('index_url = %s\n' % (easy_index,))
+        output.write('allow_hosts = %s\n' % (urlparse(easy_index).netloc,))
 
 
 def backup_configs(home):