adb: add missing condition_variable include

Test: build still works
Change-Id: I0e77336bab2a4a54cb2e77143162627d47aac0b1
diff --git a/adb/client/usb_libusb.cpp b/adb/client/usb_libusb.cpp
index a5e6f23..18f585d 100644
--- a/adb/client/usb_libusb.cpp
+++ b/adb/client/usb_libusb.cpp
@@ -22,6 +22,7 @@
 
 #include <atomic>
 #include <chrono>
+#include <condition_variable>
 #include <memory>
 #include <mutex>
 #include <string>