fix(seccompagent): close received FDs, not loop index

Prevents accidentally closing 0/1/2 on error paths.

Signed-off-by: Joshua Rogers <MegaManSec@users.noreply.github.com>
(cherry picked from commit 8c1b3f9608)
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

tests/cmd/seccompagent/seccompagent.go

@@ -27,8 +27,8 @@ var (
 )
 
 func closeStateFds(recvFds []int) {
-	for i := range recvFds {
-		unix.Close(i)
+	for _, fd := range recvFds {
+		_ = unix.Close(fd)
 	}
 }