remove duplicate networkx from pip_requirements.txt

Change-Id: I57640009e508f6cc8dbef5177d86e84ec628ac30
diff --git a/containers/xos/pip_requirements.txt b/containers/xos/pip_requirements.txt
index ac8bdb5..9a5956b 100644
--- a/containers/xos/pip_requirements.txt
+++ b/containers/xos/pip_requirements.txt
@@ -87,7 +87,6 @@
 ndg-httpsclient==0.4.2
 netaddr==0.7.18
 netifaces==0.10.5
-networkx==1.11
 nose==1.3.7
 oauth2client==3.0.0
 openapi-codec==1.0.0