Don't store temporary mail merge file if mail merge job was cancelled

If a mail merge "to single file" is canceled, the temporary file was still saved.
This needed a lot of time for large mail merge results (>20s) which is not needed,
wanted and inteded. We want mail merge to return asap.

Change-Id: I74e9048c7eb483766e7e677dd21167b7d844a518
Reviewed-on: https://gerrit.libreoffice.org/14811Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>

sw/source/uibase/dbui/dbmgr.cxx

@@ -1420,6 +1420,8 @@ bool SwDBManager::MergeMailFiles(SwWrtShell* pSourceShell,
             else if(bCreateSingleFile)
             {
                 if( rMergeDescriptor.nMergeType != DBMGR_MERGE_PRINTER )
+                {
+                    if( !bCancel )
                     {
                         assert( aTempFile.get());
                         INetURLObject aTempFileURL( rMergeDescriptor.bSubjectIsFilename ? sSubject : aTempFile->GetURL());
@@ -1444,6 +1446,7 @@ bool SwDBManager::MergeMailFiles(SwWrtShell* pSourceShell,
                             bNoError = false;
                         }
                     }
+                }
                 else if( pTargetView ) // must be available!
                 {
                     //print the target document