Simplify adb_thread_create.

Change-Id: I36d6021ef8fbc23e8bcd4ddbe1dac0eba467cc70
diff --git a/adb/usb_windows.cpp b/adb/usb_windows.cpp
index d2bd58c..1d6ec8c 100644
--- a/adb/usb_windows.cpp
+++ b/adb/usb_windows.cpp
@@ -181,9 +181,7 @@
 }
 
 void usb_init() {
-  adb_thread_t tid;
-
-  if(adb_thread_create(&tid, device_poll_thread, NULL)) {
+  if (!adb_thread_create(device_poll_thread, nullptr)) {
     fatal_errno("cannot create input thread");
   }
 }