fix get os info

src/common/helpers.py

@@ -992,8 +992,10 @@ def get_os_info():
             p.wait()
             output = temp_failure_retry(p.stdout.readline).strip()
             # some distros put n/a in places, so remove those
-            output = output.replace('n/a', '').replace('N/A', '')
+            output = output.decode('utf-8').replace('n/a', '').replace('N/A', '')
             gajim.os_info = output
+            p.stdout.close()
+            p.stdin.close()
             return output
 
         # lsb_release executable not available, so parse files

src/roster_window.py

@@ -1518,7 +1518,7 @@ class RosterWindow:
                     self.tree.collapse_row(path)
                 else:
                     self.tree.expand_row(path, False)
-        self.modelfilter.foreach(func)
+        self.modelfilter.foreach(func, None)
 
     def _adjust_account_expand_collapse_state(self, account):
         """
@@ -4441,7 +4441,7 @@ class RosterWindow:
                 col = self.tree.get_column(0)
                 self.tree.set_cursor_on_cell(path, col)
                 return True
-        self.modelfilter.foreach(_func)
+        self.modelfilter.foreach(_func, None)
 
     def on_rfilter_entry_icon_press(self, widget, icon, event):
         """