prevent warnings, fixes #4521

Closes #4521

Merge request studip/studip!3317

lib/raumzeit/CycleData.php

@@ -315,7 +315,7 @@ class CycleData
                 unset($termin);
                 $termin = new SingleDate();
                 $termin->fillValuesFromArray($val);
-                $termin->setExTermin($val['ex_termin']);
+                $termin->setExTermin(!empty($val['ex_termin']));
                 $this->termine[$val['termin_id']] = $termin;
             }
             return TRUE;

lib/raumzeit/SingleDate.php

@@ -370,7 +370,7 @@ class SingleDate
 
         if (!$name) {
             $holy_type = holiday($this->date);
-            $name = $holy_type['name'];
+            $name = $holy_type ? $holy_type['name'] : null;
         }
 
         if ($name) {