Fix double close

Accidentally made file references not count as references and therefore also close the fd. My bad.
4 jobs for master in 8 minutes and 29 seconds (queued for 3 seconds)
Name Stage Failure
failed
fmt Test
+            set.clear();
+ }
+ if let Some(ref mut set) = exceptfds {
+ set.clear();
+ }

for event in &events[..read] {
if event.data == TIMEOUT_TOKEN {
ERROR: Job failed: exit code 1
failed
test:linux Test
-connect(4, 0x7fff4f721420, 16)
-connect(4, 0x7fff4f721420, 16) = 0 (0, Success)
-sendto(4, 0x55a4352eda30, 38, 0x0, 0x0, 0)
-sendto(4, 0x55a4352eda30, 38, 0x0, 0x0, 0) = 38 (0, Success)
-recvfrom(4, 0x7fff4f7214d0, 65536, 0x0, 0x0, 0x0)
-recvfrom(4, 0x7fff4f7214d0, 65536, 0x0, 0x0, 0x0) = 82 (0, Success)
Makefile:128: recipe for target 'verify' failed
make: *** [verify] Error 1
ERROR: Job failed: exit code 1