Fix browser warnings on PDF plugin detection (#1489118)

CHANGELOG

@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix browser warnings on PDF plugin detection (#1489118)
 - Fix fatal error when parsing UUencoded messages (#1489119)
 
 RELEASE 0.9.1

program/js/app.js

@@ -6809,15 +6809,6 @@ function rcube_webmail()
         return 1;
     }
 
-    // this will detect any pdf plugin including PDF.js in Firefox
-    var obj = document.createElement('OBJECT');
-    obj.onload = function() { rcmail.env.browser_capabilities.pdf = 1; };
-    obj.onerror = function() { rcmail.env.browser_capabilities.pdf = 0; };
-    obj.style.display = 'none';
-    obj.type = 'application/pdf';
-    obj.data = 'program/resources/blank.pdf';
-    document.body.appendChild(obj);
-
     return 0;
   };