Add python-netaddr module to ansible to address the build failure

Change-Id: I0f0990c33535379a44008855979a4cacc37fdeab
diff --git a/requirements.txt b/requirements.txt
index bb31099..d62ddd5 100755
--- a/requirements.txt
+++ b/requirements.txt
@@ -15,7 +15,7 @@
 jsonpatch>=1.14
 kafka_python>=1.3.1
 klein>=15.3.1
-netaddr>=0.7.18
+netaddr>=0.7.19
 networkx>=1.11
 nose>=1.3.7
 nose-exclude>=0.5.0