updated logict to better manage retrieving data from hostvars

library/cassandra_hosts.py

diff --git a/library/cassandra_hosts.py b/library/cassandra_hosts.py
index 62925d7..553afe5 100644
--- a/library/cassandra_hosts.py
+++ b/library/cassandra_hosts.py
@@ -31,12 +31,23 @@
     for cassandra_group_name in cassandra_groups:
         cassandra_ip_mappings[cassandra_group_name] = {}
         for ds_ip in cassandra_groups[cassandra_group_name]:
-            hostvar = hostvars[ds_ip]
-            try:
-                private_ip = hostvar[LOCAL_ADDRESS]
-            except KeyError as e:
-                hostvar[LOCAL_ADDRESS] = "{0}: {1}".format(NOT_DEFINED, e)
-                private_ip = hostvar[LOCAL_ADDRESS]
+            if ds_ip in hostvars:
+                hostvar = hostvars[ds_ip]
+                if LOCAL_ADDRESS in hostvar:
+                    private_ip = hostvar[LOCAL_ADDRESS]
+                else:
+                    private_ip = NOT_DEFINED
+
+            # try:
+            #     hostvar = hostvars[ds_ip]
+            # except KeyError as e:
+            #     hostvar[ds_ip] = '{0}: {1}'.format(NOT_DEFINED, e)
+
+            # try:
+            #     private_ip = hostvar[LOCAL_ADDRESS]
+            # except KeyError as e:
+            #     hostvar[LOCAL_ADDRESS] = "{0}: {1}".format(NOT_DEFINED, e)
+            #     private_ip = hostvar[LOCAL_ADDRESS]
 
             cassandra_ip_map = cassandra_ip_mappings[cassandra_group_name]
             cassandra_ip_map[ds_ip] = { 'private_ip': private_ip }