avoid handling generic exceptions

Author: DivineThreepwood

module/schedule/src/main/java/org/openbase/jul/schedule/AbstractSynchronizationFuture.java

@@ -113,7 +113,7 @@ private T waitForSynchronization(final T message, final long timeout, final Time
         try {
             try {
                 beforeWaitForSynchronization(message);
-            } catch (final Exception ex) {
+            } catch (final CouldNotPerformException ex) {
                 throw new CouldNotPerformException("Pre execution task failed!", ex);
             }