valgrind: jump or move depends on uninitialised value

Change-Id: I02e507f4b7d78efacc5b735ca24adb83633749b9
(cherry picked from commit dcbef55a)
Reviewed-on: https://gerrit.libreoffice.org/20479Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>

lotuswordpro/source/filter/lwpfilter.cxx

@@ -148,8 +148,8 @@ using namespace OpenStormBento;
 {
     SvStream * pDecompressed = NULL;
 
-    sal_uInt32 nTag;
     pStream->Seek(0x10);
+    sal_uInt32 nTag(0);
     pStream->ReadUInt32( nTag );
     if (nTag != 0x3750574c) // "LWP7"
     {