Support multiple IPs for agent to ping, use 0s instead of nulls for speedtest

Change-Id: I68290906d808f652b324bccc44f6935ea662b7e2
diff --git a/edge-monitoring/agent_adb/edge_monitoring_agent_adb.py b/edge-monitoring/agent_adb/edge_monitoring_agent_adb.py
index 9d808b5..472cca2 100755
--- a/edge-monitoring/agent_adb/edge_monitoring_agent_adb.py
+++ b/edge-monitoring/agent_adb/edge_monitoring_agent_adb.py
@@ -79,10 +79,10 @@
     'speedtest': {
         'ping': {
             'dns': {
-                'min': None,
-                'avg': None,
-                'max': None,
-                'stddev': None
+                'min': 0.0,
+                'avg': 0.0,
+                'max': 0.0,
+                'stddev': 0.0
             }
         }
     }
@@ -156,10 +156,10 @@
     Input: IP to ping, # times to ping
     Returns: dict of the min/avg/max/stddev numbers from the ping command result
     '''
-    result = {'min': None,
-              'avg': None,
-              'max': None,
-              'stddev': None}
+    result = {'min': 0.0,
+              'avg': 0.0,
+              'max': 0.0,
+              'stddev': 0.0}
     try:
         commandResult, commandOutput = _run_adb_shell(adb, ADB_GET_COMMANDS['ping_dns_result'])
         pingResult = commandOutput.split("/")