Fix data member access outside 'this' context

c++/src/capnp/compiler/node-translator.c++

@@ -98,7 +98,7 @@ public:
     }
 
     void addHolesAtEnd(UIntType lgSize, UIntType offset,
-                       UIntType limitLgSize = sizeof(holes) / sizeof(holes[0])) {
+                       UIntType limitLgSize = sizeof(HoleSet::holes) / sizeof(HoleSet::holes[0])) {
       // Add new holes of progressively larger sizes in the range [lgSize, limitLgSize) starting
       // from the given offset.  The idea is that you just allocated an lgSize-sized field from
       // an limitLgSize-sized space, such as a newly-added word on the end of the data segment.