Reinstall requests on Fedora builds

The fedora-minimal builds do not include the package python-requests,
but some of the later puppet (via zuul) will end up pip-installing it.

This leaves the system in a very precarious state -- if the
python-requests package ever gets installed over the pip-installed
package everything is broken because of the vendoring/symlinking
issues mentioned in the comment.

This is the most logical place to fix this up so we're in a consistent
state with a pip-managed requests package.  Devstack can clean this up
(I6b06dcd897999e0642b387e8d13a473934ed0956) but better to have the
base system in a consistent state.

Change-Id: If3f244ed4f62da25dc42813b4bda2f374f002517

install_puppet.sh

@@ -102,6 +102,21 @@ function setup_puppet_fedora {
     #   https://bugzilla.redhat.com/show_bug.cgi?id=1254616
     sudo sed -i.bak  '/^[^#].*/ s|\(^.*confine :exists => \"/run/systemd/system\".*$\)|#\ \1|' \
         /usr/share/ruby/vendor_ruby/puppet/provider/service/systemd.rb
+
+    # upstream "requests" pip package vendors urllib3 and chardet
+    # packages.  The fedora packages un-vendor this, and symlink those
+    # sub-packages back to packaged versions.  We get into a real mess
+    # of if some of the puppet ends up pulling in "requests" from pip,
+    # and then something like devstack does a "yum install
+    # python-requests" which does a very bad job at overwriting the
+    # pip-installed version (symlinks and existing directories don't
+    # mix).  The solution is to pre-install the python-requests
+    # package; clear it out and re-install from pip.  This way, the
+    # package is installed for dependencies, and we have a pip-managed
+    # requests with correctly vendored sub-packages.
+    sudo ${YUM} install -y python-requests
+    sudo rm -rf /usr/lib/python2.7/site-packages/requests/*
+    sudo pip install requests
 }
 
 function setup_puppet_rhel7 {