Comment 2 for bug 1455420

Reviewed: https://review.openstack.org/183964
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=19aaa9edf6a43c206cd454e5a523d7c044a32075
Submitter: Jenkins
Branch: master

commit 19aaa9edf6a43c206cd454e5a523d7c044a32075
Author: Kai Qiang Wu(Kennan) <email address hidden>
Date: Mon May 18 11:11:20 2015 +0800

    Fix the docker build image issue

    The python cryptography issue, check
    http://www.123code.blogspot.com/2014/10/fixed-installing-python-cryptography.html

    The ubuntu pip issue, check
    http://stackoverflow.com/questions/27341064/how-do-i-fix-importerror-cannot-import-name-incompleteread

    Closes-Bug: #1455420
    Change-Id: I8cb78f990c08cb527ebce3fa720537b5c03eb942