send OS version to plugin update checker

idea/src/org/jetbrains/kotlin/idea/KotlinPluginUpdater.kt

@@ -119,7 +119,7 @@ class KotlinPluginUpdater(val propertiesComponent: PropertiesComponent) : Dispos
     fun getPluginVersionFromMainRepository(): RepositoryCheckResult {
         val buildNumber = ApplicationInfo.getInstance().build.asString()
         val pluginVersion = JetPluginUtil.getPluginVersion()
-        val os = URLEncoder.encode(SystemInfo.OS_NAME, CharsetToolkit.UTF8)
+        val os = URLEncoder.encode(SystemInfo.OS_NAME + " " + SystemInfo.OS_VERSION, CharsetToolkit.UTF8)
         val uid = UpdateChecker.getInstallationUID(propertiesComponent)
         val url = "https://plugins.jetbrains.com/plugins/list?pluginId=6954&build=$buildNumber&pluginVersion=$pluginVersion&os=$os&uuid=a$uid"
         val responseDoc = HttpRequests.request(url).connect {