Python errors in GDB pretty printers

```

(gdb) p doors
Traceback (most recent call last):
File "/opt/clion-2018.2.6/bin/gdb/renderers/default/libstdcxx_printers.py", line 75, in to_string
return ('empty %s' if self.is_empty() else '%s') % self.typename
File "/opt/clion-2018.2.6/bin/gdb/renderers/default/libstdcxx_printers.py", line 58, in is_empty
return self.head.address == self.head['_M_next'] or (self.is_cxx11_abi and self._get_data(self.head) == 0)
File "/opt/clion-2018.2.6/bin/gdb/renderers/default/libstdcxx_printers.py", line 52, in _get_data
storage = varobj['_M_storage']
gdb.error: There is no member or method named _M_storage.

```

`doors` is a `std::list<int>`. What is going on?