Use same version of python-dateutil everywhere

component/jupyter-py2/buildout.cfg

@@ -122,11 +122,6 @@ pexpect = 4.2.1
 # ipython==5.3.0
 pickleshare = 0.7.4
 
-# Required by:
-# matplotlib==2.1.2
-# pandas==0.19.2
-python-dateutil = 2.6.0
-
 # Required by:
 # pathlib2==2.2.1
 scandir = 1.5

software/jupyter/software.cfg

@@ -130,10 +130,6 @@ pickleshare = 0.7.4
 # notebook==6.1.5
 prometheus-client = 0.9.0
 
-# Required by:
-# statsmodels==0.11.1
-python-dateutil = 2.8.1
-
 # Required by:
 # pathlib2==2.2.1
 scandir = 1.5

software/neoppod/software-common.cfg

@@ -133,7 +133,6 @@ pycrypto = 2.6.1
 pycurl = 7.43.0
 setproctitle = 1.1.10
 cython-zstd = 0.2
-python-dateutil = 2.7.3
 
 # Required by:
 # mock = 3.0.5