Update per code review

src/CBLDatabase.cc

@@ -164,15 +164,8 @@ Retained<CBLCollection> CBLDatabase::getCollection(slice collectionName, slice s
     if (!c4col) {
         return nullptr;
     }
-
-    auto scope = getScope(scopeName);
-    if (!scope) {
-        // Note (Edge Case):
-        // The scope is NULL because at the same time, its all collections including the
-        // the one just created were deleted on a different thread using another database.
-        return nullptr;
-    }
-    return createCBLCollection(c4col, scope.get());
+    auto scope = new CBLScope(scopeName, this);
+    return new CBLCollection(c4col, scope, this);
 }
 
 
@@ -184,9 +177,8 @@ Retained<CBLCollection> CBLDatabase::createCollection(slice collectionName, slic
 
     auto spec = C4Database::CollectionSpec(collectionName, scopeName);
     auto c4col = c4db->createCollection(spec);
-
     auto scope = new CBLScope(scopeName, this);
-    return createCBLCollection(c4col, scope);
+    return new CBLCollection(c4col, scope, this);
 }