generator: Fix misleading warning for callbacks in virtual methods
generator: Fix misleading warning for callbacks in virtual methods

Wen generating a virtual method, the current member was not set in the
GenerationInfo. That caused the warning message about the callback scope
to refer to a wrong method name.

antoniusriha/gtk-sharp,orion75/gtk-sharp,antoniusriha/gtk-sharp,antoniusriha/gtk-sharp,antoniusriha/gtk-sharp,openmedicus/gtk-sharp,openmedicus/gtk-sharp,Gankov/gtk-sharp,sillsdev/gtk-sharp,sillsdev/gtk-sharp,sillsdev/gtk-sharp,Gankov/gtk-sharp,orion75/gtk-sharp,orion75/gtk-sharp,akrisiun/gtk-sharp,orion75/gtk-sharp,openmedicus/gtk-sharp,openmedicus/gtk-sharp,openmedicus/gtk-sharp,Gankov/gtk-sharp,openmedicus/gtk-sharp,antoniusriha/gtk-sharp,akrisiun/gtk-sharp,Gankov/gtk-sharp,sillsdev/gtk-sharp,orion75/gtk-sharp,akrisiun/gtk-sharp,Gankov/gtk-sharp,akrisiun/gtk-sharp,Gankov/gtk-sharp,sillsdev/gtk-sharp,akrisiun/gtk-sharp,openmedicus/gtk-sharp