fixed NPE when no images exist

Author: rsehr

src/main/java/de/sub/goobi/helper/FilesystemHelper.java

@@ -188,7 +188,7 @@ public static boolean isOcrFileExists(Process inProcess, String ocrFile) {
                 StorageProviderInterface sp = StorageProvider.getInstance();
                 return sp.isFileExists(xml) || sp.isFileExists(txt) || sp.isFileExists(alto);
             }
-        } catch (SwapException | IOException e) {
+        } catch (SwapException | IOException | NullPointerException e) {
             return false;
         }
     }

src/main/java/de/sub/goobi/metadaten/Metadaten.java

@@ -3605,6 +3605,9 @@ public String SeitenWeg() {
      */
 
     public boolean isImageHasOcr() {
+        if (image == null || StringUtils.isBlank(image.getTooltip())) {
+            return false;
+        }
         return FilesystemHelper.isOcrFileExists(myProzess, image.getTooltip().substring(0, image.getTooltip().lastIndexOf(".")));
     }