[EN-1818] better place for warning

Author: iamishalkin

dxfeed/core/DXFeedPy.pyx

@@ -306,6 +306,7 @@ def dxf_attach_listener(SubscriptionClass sc):
     event_handler = sc.get_event_handler()
     if not event_handler:
         raise ValueError('Event handler is not defined!')
+    warn(FutureWarning('New order in event fields will be introduced in dxfeed-0.6.0. Address event fields by name.'))
 
     if sc.event_type_str == 'Trade':
         event_handler.columns = lis.TRADE_COLUMNS

dxfeed/core/listeners/listener.pyx

@@ -1,10 +1,7 @@
 from dxfeed.core.utils.helpers cimport *
 from dxfeed.core.utils.handler cimport EventHandler
-from logging import warning
 
 
-warning(FutureWarning('New order in event fields will be introduced in dxfeed-0.6.0. Address event fields by name.'))
-
 cdef class FuncWrapper:
     def __cinit__(self):
         self.func = NULL