(installer) don't check for an running Zero-K.exe when running silent

installer/spring.nsi

@@ -156,6 +156,7 @@ Function .onInit
 		; check if we need to exit some processes which may be using unitsync
 		${CheckExecutableRunning} "TASClient.exe" "TASClient"
 		${CheckExecutableRunning} "springlobby.exe" "Spring Lobby"
+		IfSilent +2 ; Zero-K installs this silent, so don't check
 		${CheckExecutableRunning} "Zero-K.exe" "Zero-K Lobby"
 		${CheckExecutableRunning} "CADownloader.exe" "CA Downloader"
 		${CheckExecutableRunning} "springsettings.exe" "Spring Settings"