MXS-2011 Change return value of blr_check_connect_retry

0 cannot be used to indicate failure as 0 will be the waiting
period if we switch to an alternative server.

Also fix some minor issues; failure to initialize all members
and inverted success-check.

server/modules/routing/binlogrouter/blr.hh

@@ -378,6 +378,8 @@ public:
 
     ChangeMasterConfig(const char* name)
         : connection_name(name)
+        , port(-1)
+        , ssl_enabled(false)
         , heartbeat_period(BLR_HEARTBEAT_DEFAULT_INTERVAL_VALUE)
         , connect_retry(BLR_MASTER_CONNECT_RETRY_VALUE)
     {