[mod] upgrade versions in requirements.txt

requirements.txt

 certifi==2016.9.26
-flask==0.11.1
+flask==0.12
 flask-babel==0.11.1
-lxml==3.6.0
-ndg-httpsclient==0.4.1
+lxml==3.7.1
+ndg-httpsclient==0.4.2
 pyasn1==0.1.9
 pyasn1-modules==0.0.8
 pygments==2.1.3
-pyopenssl==0.15.1
+pyopenssl==16.2.0
 python-dateutil==2.5.3
 pyyaml==3.11
-requests[socks]==2.10.0
+requests[socks]==2.12.4