adb: fix mac build breakage.

Bug: http://b/129786641
Test: none
Change-Id: Ibe051a0db2f912d1f7e55369e25a5bd38bf86fd5
diff --git a/adb/client/usb_osx.cpp b/adb/client/usb_osx.cpp
index 381ded4..5c0da47 100644
--- a/adb/client/usb_osx.cpp
+++ b/adb/client/usb_osx.cpp
@@ -557,9 +557,7 @@
 }
 
 void usb_reset(usb_handle* handle) {
-    if (!handle->dead) {
-        (*handle->interface)->USBDeviceReEnumerate(handle->interface, 0);
-    }
+    // Unimplemented on OS X.
     usb_kick(handle);
 }