fileOperation: Corrected findInstance. See also #974.

Patch contributed by Mattijs Janssens

src/OpenFOAM/global/fileOperations/fileOperation/fileOperation.C

@@ -784,7 +784,11 @@ Foam::IOobject Foam::fileOperation::findInstance
     for (; instanceI >= 0; --instanceI)
     {
         // Shortcut: if actual directory is the timeName we've already tested it
-        if (ts[instanceI].name() == startIO.instance())
+        if
+        (
+            ts[instanceI].name() == startIO.instance()
+         && ts[instanceI].name() != stopInstance
+        )
         {
             continue;
         }