Revert "Split adb_main.cpp into client and daemon."

This reverts commit cf07494ac2a101c3afbe23a7d85121553f586cf7.
diff --git a/adb/adb.h b/adb/adb.h
index 7942a86..daabf8c 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -324,6 +324,7 @@
 
 /* usb host/client interface */
 void usb_init();
+void usb_cleanup();
 int usb_write(usb_handle *h, const void *data, int len);
 int usb_read(usb_handle *h, void *data, int len);
 int usb_close(usb_handle *h);