resources: Remove deprecate HBox/VBox from commit dialog

Author: Me

meld/resources/ui/commit-dialog.ui

@@ -17,12 +17,14 @@
         <property name="orientation">vertical</property>
         <property name="spacing">18</property>
         <child>
-          <object class="GtkVBox" id="vbox0">
+          <object class="GtkBox" id="vbox0">
+            <property name="orientation">vertical</property>
             <property name="visible">True</property>
             <property name="can_focus">False</property>
             <property name="spacing">18</property>
             <child>
-              <object class="GtkVBox" id="vbox1">
+              <object class="GtkBox" id="vbox1">
+                <property name="orientation">vertical</property>
                 <property name="visible">True</property>
                 <property name="can_focus">False</property>
                 <property name="spacing">6</property>
@@ -43,7 +45,8 @@
                   </packing>
                 </child>
                 <child>
-                  <object class="GtkHBox" id="hbox1">
+                  <object class="GtkBox" id="hbox1">
+                    <property name="orientation">horizontal</property>
                     <property name="visible">True</property>
                     <property name="can_focus">False</property>
                     <child>
@@ -101,7 +104,8 @@
               </packing>
             </child>
             <child>
-              <object class="GtkVBox" id="vbox2">
+              <object class="GtkBox" id="vbox2">
+                <property name="orientation">vertical</property>
                 <property name="visible">True</property>
                 <property name="can_focus">False</property>
                 <property name="spacing">6</property>
@@ -122,7 +126,8 @@
                   </packing>
                 </child>
                 <child>
-                  <object class="GtkHBox" id="hbox4">
+                  <object class="GtkBox" id="hbox4">
+                    <property name="orientation">horizontal</property>
                     <property name="visible">True</property>
                     <property name="can_focus">False</property>
                     <child>
@@ -138,7 +143,8 @@
                       </packing>
                     </child>
                     <child>
-                      <object class="GtkVBox" id="vbox3">
+                      <object class="GtkBox" id="vbox3">
+                        <property name="orientation">vertical</property>
                         <property name="visible">True</property>
                         <property name="can_focus">False</property>
                         <property name="spacing">6</property>
@@ -163,7 +169,8 @@
                           </packing>
                         </child>
                         <child>
-                          <object class="GtkHBox" id="previousbox">
+                          <object class="GtkBox" id="previousbox">
+                            <property name="orientation">horizontal</property>
                             <property name="visible">True</property>
                             <property name="can_focus">False</property>
                             <property name="spacing">12</property>