Revert "PLAT-2060 Use pip-tools to manage requirements files"

common/lib/capa/capa/safe_exec/README.rst

@@ -19,6 +19,8 @@ __ https://github.com/edx/codejail/blob/master/README.rst
    need to install the requirements from requirements/edx-sandbox::
 
     $ pip install -r requirements/edx-sandbox/base.txt
+    $ pip install -r requirements/edx-sandbox/local.txt
+    $ pip install -r requirements/edx-sandbox/post.txt
 
 2. At the instruction to create the AppArmor profile, you'll need a line in
    the profile for the sandbox packages.  <EDXPLATFORM> is the full path to

common/lib/chem/setup.py

@@ -8,6 +8,6 @@ setup(
         "pyparsing==2.2.0",
         "numpy==1.6.2",
         "scipy==0.14.0",
-        "nltk",
+        "nltk==3.2.5",
     ],
 )