Upgrade: Fix SLED 12 SP3 upgrade path (BSC#1191832)

Author: cwickert

xml/sle_update_upgrading.xml

@@ -200,7 +200,7 @@
     <term>Upgrading from &productname; 12 GA / SP1 / SP2 / SP3 / SP4</term>
     <listitem>
      <para>
-      Upgrading from &productnameshort;&nbsp;12&nbsp;SP4 or older service packs
+      Upgrading from &productnameshort;&nbsp;12&nbsp;SP3 or older service packs
       directly is not supported. You need at least
       &productnameshort;&nbsp;12&nbsp;SP5 before you can proceed to
       &productnameshort;&nbsp;&productnumber;.