Squelch errors from open_basedir restrictions

When reading data from /dev/urandom and friends on *nix systems with the
open_basedir setting enforced.

include/PasswordHash.php

@@ -48,7 +48,7 @@ class PasswordHash {
 	function get_random_bytes($count)
 	{
 		$output = '';
-		if (is_readable('/dev/urandom') &&
+		if (@is_readable('/dev/urandom') &&
 		    ($fh = @fopen('/dev/urandom', 'rb'))) {
 			$output = fread($fh, $count);
 			fclose($fh);

include/pear/Auth/SASL/DigestMD5.php

@@ -178,10 +178,10 @@ class Auth_SASL_DigestMD5 extends Auth_SASL_Common
     */
     function _getCnonce()
     {
-        if (file_exists('/dev/urandom') && $fd = @fopen('/dev/urandom', 'r')) {
+        if (@file_exists('/dev/urandom') && $fd = @fopen('/dev/urandom', 'r')) {
             return base64_encode(fread($fd, 32));
 
-        } elseif (file_exists('/dev/random') && $fd = @fopen('/dev/random', 'r')) {
+        } elseif (@file_exists('/dev/random') && $fd = @fopen('/dev/random', 'r')) {
             return base64_encode(fread($fd, 32));
 
         } else {