Fixing attributes to allow &default in tables/sets to be associated

with the field.

This works now:

    type X: record {
        a: table[string] of bool &default=table( ["foo"] = T );
        b: table[string] of bool &default=table();
        c: set[string] &default=set("A", "B", "C");
        d: set[string] &default=set();
    };

I think previously the intend was to associate &default with the
table/set (i.e., define the default value for non-existing indices).
However, that was already not working: the error checking was
reporting type mismatches. So, this shouldn't break anything and make
things more consistent.

src/Attr.h

@@ -62,7 +62,7 @@ protected:
 // Manages a collection of attributes.
 class Attributes : public BroObj {
 public:
-	Attributes(attr_list* a, BroType* t);
+	Attributes(attr_list* a, BroType* t, bool in_record);
 	~Attributes();
 
 	void AddAttr(Attr* a);
@@ -87,6 +87,7 @@ protected:
 
 	BroType* type;
 	attr_list* attrs;
+	bool in_record;
 };
 
 #endif