Make :set work correctly

TODO

@@ -2,7 +2,6 @@ New config TODO
 ===============
 
 - Changing models is awfully slow
-- Add correctly working :get and :set commands
 - Implement different layers of config options correctly, not only default.
 
 Bugs

qutebrowser/config/config.py

@@ -219,11 +219,8 @@ class Config:
         if value:
             value = self._interpolation.before_set(self, section, option,
                                                    value)
-        if not section or section == self.default_section:
-            sectdict = self._defaults
-        else:
         try:
-                sectdict = self._sections[section]
+            sectdict = self.config[section]
         except KeyError:
             raise NoSectionError(section)
         sectdict[self.optionxform(option)] = value