Fix requirements when installing from source

Nova fails to work with some versions of cryptography so we have
to adjust for the version that nova sets in its own requirements,
this makes us set pyOpenSSL < 16.0.0 because it does not work with
the version of cryptograpy that gets installed when it's constrained
to: cryptography!=1.3.0,>=1.0.

Change-Id: I59fbaab8e8034916fb41ee76b429469982bd7d39

requirements.txt

@@ -1,5 +1,5 @@
 netaddr>=0.7.6
 PyYAML>=3.10
 docutils>=0.11
-pyOpenSSL
-cryptography
+cryptography!=1.2.2,>=1.0
+pyOpenSSL<15.0.0

setup.py

@@ -104,7 +104,8 @@ setup(
     include_package_data=True,
     long_description=read('README.md'),
     zip_safe=False,
-    install_requires=['netaddr', 'pyOpenSSL', 'PyYAML', 'docutils'],
+    install_requires=['netaddr>=0.7.6', 'pyOpenSSL<15.0.0', 'PyYAML>=3.10',
+                      'docutils>=0.11', 'cryptography<=1.2.2,>=1.0'],
     classifiers=[
         "Development Status :: 3 - Alpha",
         "Topic :: Utilities",