Fix the file filters for InsetInclude.

Add an empty filter for listings and verbatim includes. This will
display as the standard string "All files (*)".

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@39673 a592a061-630c-0410-9148-cb99ea01b6c8

src/frontends/qt4/GuiInclude.cpp

@@ -323,6 +323,7 @@ QString GuiInclude::browse(QString const & in_name, Type in_type) const
 		break;
 	case VERBATIM:
 	case LISTINGS:
+		filters = fileFilters(QString());
 		break;
 	}