Delay field access until after export check.
Delay field access until after export check.

Since unexported fields are skipped, don't needlessly get the
reflect.Value for the field until after the test.

dajohi/go-xdr,rasky/go-xdr,dajohi/go-xdr,postfix/go-xdr,rasky/go-xdr,postfix/go-xdr,nullstyle/go-xdr,davecgh/go-xdr,nullstyle/go-xdr,davecgh/go-xdr