don't configure log level if the item does not exist in the config

Reported here:
https://github.com/gustavo-iniguez-goya/opensnitch/issues/31#issuecomment-633759613

The LogLevel conf item should always exist, but just in case.

daemon/ui/client.go

@@ -33,7 +33,7 @@ type Config struct {
 	DefaultDuration   string
 	InterceptUnknown  bool
 	ProcMonitorMethod string
-	LogLevel          uint32
+	LogLevel          *uint32
 }
 
 // Client holds the connection information of a client.

daemon/ui/config.go

@@ -47,7 +47,9 @@ func (c *Client) loadConfiguration(rawConfig []byte) bool {
 		clientDisconnectedRule.Duration = rule.Duration(config.DefaultDuration)
 		clientErrorRule.Duration = rule.Duration(config.DefaultDuration)
 	}
-	log.MinLevel = int(config.LogLevel)
+	if config.LogLevel != nil {
+		log.MinLevel = int(*config.LogLevel)
+	}
 	if config.ProcMonitorMethod != "" {
 		procmon.MonitorMethod = config.ProcMonitorMethod
 	}