Fix the way to check for an existing entry

Instead of requiring more than 1 entry (> 1) we have to check for at least one entry (> 0)

src/Wallabag/CoreBundle/Repository/EntryRepository.php

@@ -242,8 +242,8 @@ class EntryRepository extends EntityRepository
             ->getQuery()
             ->getResult();
 
-        if (count($res) > 1) {
-            return next($res);
+        if (count($res)) {
+            return current($res);
         }
 
         return false;