Squelch MSVC warnings. It doesn't know that DISSECTOR_ASSERT_NOT_REACHED doesn't

return.

svn path=/trunk/; revision=50939

epan/proto.c

@@ -5391,6 +5391,11 @@ hf_try_val64_to_str(guint64 value, const header_field_info *hfinfo)
 	/* If this is reached somebody registered a 64-bit field with a 32-bit
 	 * value-string, which isn't right. */
 	DISSECTOR_ASSERT_NOT_REACHED();
+
+	/* This is necessary to squelch MSVC errors; is there
+	   any way to tell it that DISSECTOR_ASSERT_NOT_REACHED()
+	   never returns? */
+	return NULL;
 }
 
 static const char *