refs #20946 [finc] corrects syntactical errors

* add src for ajax skeleton img
* fix for cover: avoid exception for empty file name (FincMissing)
* log exceptions of wachtl loan history call

module/finc/src/finc/Cover/Loader.php

@@ -59,7 +59,7 @@ class Loader extends \VuFind\Cover\Loader
     public function loadUnavailable()
     {
         $this->hasLoadedUnavailable = true;
-        if ($this->config->Content->useCoverFallbacksOnFail) {
+        if ($this->config->Content->useCoverFallbacksOnFail && !empty($this->localFile)) {
             file_put_contents($this->localFile, self::EMPTY_IMAGE_CONTENT);
         }
         return parent::loadUnavailable();

module/finc/src/finc/ILS/Driver/LiberoWachtlTrait.php

@@ -659,6 +659,9 @@ trait LiberoWachtlTrait
                 $this->getLiberoWachtlRequestHeaders()
             );
         } catch (\Exception $e) {
+            $this->debug(
+                'Error loading loan history from LiberoWachtl: ' . $e->getMessage()
+            );
             throw new ILSException($e->getMessage());
         }
         if (!$result->isSuccess()) {

themes/finc/templates/record/cover.phtml

@@ -27,7 +27,7 @@
       <div class="cover-container">
         <?=$this->render('record/coverReplacement')?>
         <a class="coverlink hidden" aria-hidden="true" tabindex="-1">
-          <img <?php if ($linkPreview): ?>data-linkpreview="true" <?php endif; ?> class="recordcover ajax" alt="<?=$this->escapeHtmlAttr($alt); ?>" />
+          <img <?php if ($linkPreview): ?>data-linkpreview="true" <?php endif; ?> class="recordcover ajax" src="<?=$this->imageLink('noCover2.gif')?>" alt="<?=$this->escapeHtmlAttr($alt); ?>" />
         </a>
         <script>
           loadCoverByElement({source:'<?=$this->escapeHtmlAttr($driver->getSourceIdentifier())?>', recordId:'<?=$this->escapeHtmlAttr($driver->getUniqueID())?>', size:'<?=$this->escapeHtmlAttr($size)?>'}, $('#<?=$coverId?>'));