Support vmagent that doesn't return x-influxdb-version header

main.py

@@ -71,6 +71,10 @@ def influxb_connect(config):
             )
         client.ping()
         return client
+    except KeyError as e:
+        if e.args == ("x-influxdb-version",):
+            print("Ignoring vmagent missing x-influxdb-version header")
+        return client
     except Exception as e:
         print("Cannot connect to {} : {}".format(o.hostname, e))
         print("If InfluxDB has just started, this is normal, please wait!")