GtkFileChooserDefault: Remove redundancy

Don't specify packing properties for internal children.
This doesn't work unless the internal children are actually
direct children of the container (which we are about to
change for GtkInfoBar). Also, it is redundant, since we
just set the properties to the values they already have
anyway.

gtk/gtkfilechooserdefault.ui

@@ -122,11 +122,6 @@
                           </packing>
                         </child>
                       </object>
-                      <packing>
-                        <property name="expand">True</property>
-                        <property name="fill">True</property>
-                        <property name="position">0</property>
-                      </packing>
                     </child>
                     <child internal-child="action_area">
                       <object class="GtkButtonBox" id="infobar-action_area1">
@@ -136,11 +131,6 @@
                         <property name="spacing">6</property>
                         <property name="layout_style">end</property>
                       </object>
-                      <packing>
-                        <property name="expand">False</property>
-                        <property name="fill">True</property>
-                        <property name="position">1</property>
-                      </packing>
                     </child>
                   </object>
                   <packing>