Show an error message rather than just "unknown version"

refs #9247

application/views/scripts/about/index.phtml

@@ -13,9 +13,13 @@
             }
         }
     }
+
+    echo (
+        0 === count($versionInfo)
+            ? '<p class="fileNotReadable">' . $this->translate(
+                'Can\'t determine Icinga Web 2\'s version'
+            )
+            : '<p>' . nl2br(implode("\n", $versionInfo), false)
+    ) . '</p>';
     ?>
-    <p><?= 0 === count($versionInfo)
-        ? $this->translate('unknown version')
-        : nl2br(implode("\n", $versionInfo), false)
-    ?></p>
 </div>