tdf#171046: fix update of document statistics

Document statistics should be considered as initialized only
if the call to IncrementalDocStatCalculate() came to an end.

Change-Id: I3d83e99fb8b1cfa6c63ca0ee120275fe80c00e47
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/202041
Reviewed-by: Oliver Specht <oliver.specht@cib.de>
Tested-by: Jenkins

sw/source/core/doc/DocumentStatisticsManager.cxx

@@ -103,7 +103,6 @@ void DocumentStatisticsManager::UpdateDocStat( bool bCompleteAsync, bool bFields
 // returns true while there is more to do
 bool DocumentStatisticsManager::IncrementalDocStatCalculate(tools::Long nChars, bool bFields)
 {
-    mbInitialized = true;
     mpDocStat->Reset();
     mpDocStat->nPara = 0; // default is 1!
 
@@ -196,7 +195,7 @@ bool DocumentStatisticsManager::IncrementalDocStatCalculate(tools::Long nChars,
         SwFieldType *pType = m_rDoc.getIDocumentFieldsAccess().GetSysFieldType(SwFieldIds::DocStat);
         pType->UpdateFields();
     }
-
+    mbInitialized = nChars > 0;
     return nChars < 0;
 }