Fix: Use networkx 1.11 due to major API change in recently released networkx 2.0

This is temporary until we migrated to the latest networkx API.

Change-Id: Id735686098c8d8ab03f40f648d10aff31ba87129
Signed-off-by: peusterm <manuel.peuster@uni-paderborn.de>
diff --git a/ansible/install.yml b/ansible/install.yml
index 61d12a2..0ee1e44 100755
--- a/ansible/install.yml
+++ b/ansible/install.yml
@@ -51,7 +51,7 @@
      pip: name=argparse state=latest
 
    - name: install networkx
-     pip: name=networkx state=latest
+     pip: name=networkx version=1.11
 
    - name: install six
      pip: name=six state=latest
diff --git a/setup.py b/setup.py
index c2903f1..a28df09 100755
--- a/setup.py
+++ b/setup.py
@@ -45,7 +45,7 @@
           'pyaml',
           'tabulate',
           'argparse',
-          'networkx',
+          'networkx==1.11',
           'six>=1.9',
           'ryu',
           'oslo.config',