Fix the property for restarting syscalls (#1251)

Credit goes to @gmponos for reporting the problem.

src/Monolog/SignalHandler.php

@@ -96,7 +96,7 @@ class SignalHandler
         if ($this->previousSignalHandler[$signo] === true || $this->previousSignalHandler[$signo] === SIG_DFL) {
             if (extension_loaded('pcntl') && function_exists('pcntl_signal') && function_exists('pcntl_sigprocmask') && function_exists('pcntl_signal_dispatch')
                 && extension_loaded('posix') && function_exists('posix_getpid') && function_exists('posix_kill')) {
-                    $restartSyscalls = isset($this->restartSyscalls[$signo]) ? $this->restartSyscalls[$signo] : true;
+                    $restartSyscalls = isset($this->signalRestartSyscalls[$signo]) ? $this->signalRestartSyscalls[$signo] : true;
                     pcntl_signal($signo, SIG_DFL, $restartSyscalls);
                     pcntl_sigprocmask(SIG_UNBLOCK, array($signo), $oldset);
                     posix_kill(posix_getpid(), $signo);