test: removed on_feefilter that has never been implemented for Dash

Author: knst

test/functional/test_framework/p2p.py

@@ -578,7 +578,6 @@ def on_cfcheckpt(self, message): pass
     def on_cfheaders(self, message): pass
     def on_cfilter(self, message): pass
     def on_cmpctblock(self, message): pass
-    def on_feefilter(self, message): pass
     def on_filteradd(self, message): pass
     def on_filterclear(self, message): pass
     def on_filterload(self, message): pass