Don't assume Open means Sat when finished

Assumption doesn't hold true currently

src/lib/CoAlgReasoner.ml

@@ -244,7 +244,7 @@ let propagateSatMu () =
          (setLengthCore setCores) = (setLengthCore allowedCores)
     then begin
         setIterState (fun state -> stateSetStatus state Sat) setStates;
-        setIterCore (fun core -> coreSetStatus core Sat) setCores;
+        setIterCore (fun core -> coreSetStatus core Sat; if core == graphGetRoot () then raise (CoAlg_finished true) else ()) setCores;
       end else
       fixpointstep allowedStates allowedCores
   in
@@ -908,8 +908,8 @@ let isRootSat () =
   match coreGetStatus (graphGetRoot ()) with
   | Expandable -> None
   | Unsat -> Some false
-  | Sat
-  | Open -> if (queueIsEmpty()) then Some true else None
+  | Sat -> if (queueIsEmpty()) then Some true else None
+  | Open -> if (queueIsEmpty()) then Some false else None
 
 let reasonerFinished () =
   match coreGetStatus (graphGetRoot ()) with