Updated from global requirements

Change-Id: I562fd5272088d387e5d66314e352ff1d38ea0413

requirements.txt

@@ -10,4 +10,4 @@ oslo.utils>=3.33.0 # Apache-2.0
 setuptools!=24.0.0,!=34.0.0,!=34.0.1,!=34.0.2,!=34.0.3,!=34.1.0,!=34.1.1,!=34.2.0,!=34.3.0,!=34.3.1,!=34.3.2,!=36.2.0,>=21.0.0 # PSF/ZPL
 PyYAML>=3.12 # MIT
 netaddr>=0.7.18 # BSD
-cryptography!=2.0,>=1.9 # BSD/Apache-2.0
+cryptography>=2.1 # BSD/Apache-2.0