Add missing check for connection handler

Author: alex-kulakov

Orm/Xtensive.Orm/Orm/Configuration/DomainTypeRegistry.cs

@@ -119,7 +119,7 @@ public IEnumerable<Type> ConnectionHandlers
           }
           return connectionHandlers;
         }
-        // if instacne is not locked then there is a chance of new handlers appeared
+        // if instance is not locked then there is a chance of new handlers appeared
         return this.Where(IsConnectionHandler);
       }
     }
@@ -143,7 +143,8 @@ public static bool IsInterestingType(Type type)
         IsUpgradeHandler(type) ||
         IsKeyGenerator(type) ||
         IsCompilerContainer(type) ||
-        IsFullTextCatalogNameBuilder(type);
+        IsFullTextCatalogNameBuilder(type) ||
+        IsConnectionHandler(type);
     }
 
     /// <summary>