Issue #15556: remove unused variable

$c_private is initialized but never used in bugnote_add()'s scope.

core/bugnote_api.php

@@ -146,7 +146,6 @@ function bugnote_is_user_reporter( $p_bugnote_id, $p_user_id ) {
 function bugnote_add( $p_bug_id, $p_bugnote_text, $p_time_tracking = '0:00', $p_private = false, $p_type = 0, $p_attr = '', $p_user_id = null, $p_send_email = TRUE, $p_date_submitted = 0, $p_last_modified = 0, $p_skip_bug_update = FALSE, $p_log_history = TRUE ) {
 	$c_bug_id = db_prepare_int( $p_bug_id );
 	$c_time_tracking = helper_duration_to_minutes( $p_time_tracking );
-	$c_private = db_prepare_bool( $p_private );
 	$c_type = db_prepare_int( $p_type );
 	$c_date_submitted = $p_date_submitted <= 0 ? db_now() : db_prepare_int( $p_date_submitted );
 	$c_last_modified = $p_last_modified <= 0 ? db_now() : db_prepare_int( $p_last_modified );