sw: add back lost tree model for sendas in mmresultemaildialog

These were part of mmoutputpage previously.

With this, it's possible to send email with MM again, though we crash
before the results (were the mails sent out successfully?) could be
seen.

Change-Id: I19724e829d50aafdd20198596422be1ff079b3f5
diff --git a/sw/uiconfig/swriter/ui/mmresultemaildialog.ui b/sw/uiconfig/swriter/ui/mmresultemaildialog.ui
index fba65e5..bd79a6a 100644
--- a/sw/uiconfig/swriter/ui/mmresultemaildialog.ui
+++ b/sw/uiconfig/swriter/ui/mmresultemaildialog.ui
@@ -2,6 +2,36 @@
<!-- Generated with glade 3.18.3 -->
<interface>
  <requires lib="gtk+" version="3.0"/>
  <object class="GtkListStore" id="liststore1">
    <columns>
      <!-- column-name gchararray1 -->
      <column type="gchararray"/>
      <!-- column-name gint1 -->
      <column type="gint"/>
    </columns>
    <data>
      <row>
        <col id="0" translatable="yes">OpenDocument Text</col>
        <col id="1">1</col>
      </row>
      <row>
        <col id="0" translatable="yes">Adobe PDF-Document</col>
        <col id="1">2</col>
      </row>
      <row>
        <col id="0" translatable="yes">Microsoft Word Document</col>
        <col id="1">3</col>
      </row>
      <row>
        <col id="0" translatable="yes">HTML Message</col>
        <col id="1">4</col>
      </row>
      <row>
        <col id="0" translatable="yes">Plain Text</col>
        <col id="1">5</col>
      </row>
    </data>
  </object>
  <object class="GtkDialog" id="MMResultEmailDialog">
    <property name="can_focus">False</property>
    <property name="border_width">6</property>
@@ -177,6 +207,7 @@
                            <property name="visible">True</property>
                            <property name="can_focus">False</property>
                            <property name="hexpand">True</property>
                            <property name="model">liststore1</property>
                          </object>
                          <packing>
                            <property name="left_attach">1</property>