Race condition / segfault with __destroy hack for Windows re-enumeration

[kevinmehall]

Reproducible occasionally on Rampart (Ubuntu 14.04 x64 where 4 Tessels are updated simultaneously)

Sometimes the process hangs after Complete, sometimes it segfaults with:

Program terminated with signal SIGSEGV, Segmentation fault.                     │·······················
#0  0x0000000001642230 in ?? ()                                                 │·······················
(gdb) bt                                                                        │·······················
#0  0x0000000001642230 in ?? ()                                                 │·······················
#1  0x00007f13fb625506 in handleCompletion(Transfer*) ()                        │·······················
   from /home/rampart/cli-new/node_modules/usb/build/Release/usb_bindings.node  │·······················
#2  0x00007f13fb626435 in UVQueue<Transfer*>::internal_callback(uv_async_s*, int│·······················
) ()                                                                            │·······················
   from /home/rampart/cli-new/node_modules/usb/build/Release/usb_bindings.node  │·······················
#3  0x0000000000463609 in ?? ()                                                 │·······················
#4  0x00000000004636f3 in ?? ()                                                 │·······················
#5  0x00000000004702bc in uv.io_poll ()                                         │·······················
#6  0x0000000000463f8c in uv_run ()                                             │·······················
#7  0x0000000000426e05 in node::Start(int, char**) ()                           │·······················
#8  0x00007f13fbd67ec5 in __libc_start_main (main=0x41c810 <main>, argc=4,      │·······················
    argv=0x7fff1b9fb618, init=<optimized out>, fini=<optimized out>,            │·······················
    rtld_fini=<optimized out>, stack

Has not been observed in any single-device case, but seems to be timing-related. Commenting out the __destroy calls prevents the crash.