Fixed typo

Author: stephenchouca

src/index_notation/property_pointers.cpp

@@ -78,7 +78,7 @@ IdentityPtr::IdentityPtr(Literal identity) : PropertyPtr(), content(new Content)
 }
 
 IdentityPtr::IdentityPtr(Literal identity, std::vector<int> &p) : PropertyPtr(), content(new Content) {
- content->identity;
+ content->identity = identity;
  content->positions = p;
 }