Simplify adb_thread_create.

Change-Id: I36d6021ef8fbc23e8bcd4ddbe1dac0eba467cc70
diff --git a/adb/usb_linux_client.cpp b/adb/usb_linux_client.cpp
index 18289e2..f337ccd 100644
--- a/adb/usb_linux_client.cpp
+++ b/adb/usb_linux_client.cpp
@@ -264,8 +264,7 @@
     }
 
     D("[ usb_init - starting thread ]\n");
-    adb_thread_t tid;
-    if(adb_thread_create(&tid, usb_adb_open_thread, h)){
+    if (!adb_thread_create(usb_adb_open_thread, h)) {
         fatal_errno("cannot create usb thread");
     }
 }
@@ -483,8 +482,7 @@
     adb_mutex_init(&h->lock, 0);
 
     D("[ usb_init - starting thread ]\n");
-    adb_thread_t tid;
-    if (adb_thread_create(&tid, usb_ffs_open_thread, h)){
+    if (!adb_thread_create(usb_ffs_open_thread, h)) {
         fatal_errno("[ cannot create usb thread ]\n");
     }
 }