Window width not correctly restored in single win mode
Bug description
When starting gajim, the window width is not restored correctly, the size increases.
Steps to reproduce
Start gajim
Activate single window mode
Notice window width
Quit gajim
Start gajim
Notice window width increased
Software versions
Gajim version:0.16.6 and 0.16.10/gtk3
OS version: Windows 7
GTK+ Version: 3.18.9
PyGobject Version: 3.18.2
python-nbxmpp Version: 0.5.4