use PID as default salt

lib/AccountManager/Tools.pm

@@ -66,9 +66,10 @@ sub generate_password {
 # ID is based on time + PID
 sub generate_token {
     my ($salt, $size) = @_;
+    $salt = $PID unless $salt;
     $size = 20 unless $size;
 
-    return substr(Digest::MD5::md5_hex(time . $PID . $salt), -1 * $size);
+    return substr(Digest::MD5::md5_hex(time . $salt), -1 * $size);
 }
 
 ## Updates simpleSamlPhp authsources.php configuration file