respect `notify-on-install` option

src/Composer/Installer.php

@@ -233,13 +233,13 @@ class Installer
                 return $res;
             }
         } catch (\Exception $e) {
-            if ($this->executeOperations) {
+            if ($this->executeOperations && $this->config->get('notify-on-install')) {
                 $this->installationManager->notifyInstalls($this->io);
             }
 
             throw $e;
         }
-        if ($this->executeOperations) {
+        if ($this->executeOperations && $this->config->get('notify-on-install')) {
             $this->installationManager->notifyInstalls($this->io);
         }