coverity#706578 uncaught exception

Change-Id: I70640f42db49da274118f7336ff072b1b53ac640

package/source/xstor/xstorage.cxx

@@ -5985,6 +5985,8 @@ uno::Reference< embed::XExtendedStorageStream > SAL_CALL OStorage::openStreamEle
 
     uno::Reference< embed::XExtendedStorageStream > xResult;
     if ( aListPath.size() == 1 )
+    {
+        try
         {
             // that must be a direct request for a stream
             // the transacted version of the stream should be opened
@@ -5996,6 +5998,11 @@ uno::Reference< embed::XExtendedStorageStream > SAL_CALL OStorage::openStreamEle
                             pElement->m_pStream->GetStream( nOpenMode, true ),
                             uno::UNO_QUERY_THROW );
         }
+        catch ( const container::NoSuchElementException & )
+        {
+            throw io::IOException( THROW_WHERE ); // file not found
+        }
+    }
     else
     {
         // there are still storages in between