Changing font of chat messages to 'Exo 2' (size: 11) causes this error

Versions

• OS: Linux
• GTK+ Version: 3.22.28
• PyGObject Version: 3.26.1
• python-nbxmpp Version: 0.6.4
• Gajim Version: 1.0.0

Traceback

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/gajim/config.py", line 838, in on_conversation_fontbutton_font_set
    self.on_preference_widget_font_set(widget, 'conversation_font')
  File "/usr/lib/python3/dist-packages/gajim/config.py", line 814, in on_preference_widget_font_set
    gtkgui_helpers.load_css()
  File "/usr/lib/python3/dist-packages/gajim/gtkgui_helpers.py", line 810, in load_css
    provider.load_from_data(bytes(css.encode()))
GLib.GError: gtk-css-provider-error-quark: <data>:119:23Junk at end of value for font-family (1)

Steps to reproduce the problem

1. Got to options
2. In [Style] tab change font of chat messages to 'Exo 2' size 11 (I guess size doesn't matter only the space symbol in font name does)
3. Catch the error.
4. Since that moment Gajim doesn't start at all. It crashes with the same error.

Quick cure

Changing conversation_font = Exo 2 11 into conversation_font = "Exo 2" 11 in ~/.config/gajim/config solves the problem.