ODBC-389 alloc-dealloc mismatch

Connection handle has been changed to be allocated with new, but
deallocation has been remained old free, instead of delete

driver/ma_connection.cpp

@@ -560,7 +560,7 @@ SQLRETURN MADB_DbcFree(MADB_Dbc *Connection)
   MADB_DSN_Free(Connection->Dsn);
   DeleteCriticalSection(&Connection->cs);
 
-  free(Connection);
+  delete Connection;
   return SQL_SUCCESS;
 }
 /* }}} */