Removing default W size for gc-roster in glade. Fixes a bug where at creation,

this size replace the one we saved, everytime. Hope that doesn't create others
problems, but seems not.

data/glade/message_window.glade

@@ -450,7 +450,7 @@
                     <property name="position">495</property>
                     <child>
                       <widget class="GtkVBox" id="vbox108">
-                        <property name="width_request">150</property>
+                        <property name="width_request">0</property>
                         <property name="visible">True</property>
                         <property name="spacing">6</property>
                         <child>