fuse: Fix build error with fuzzing cfg flag
fuse: Fix build error with fuzzing cfg flag

BUG=chromium:1160986
TEST=run `RUSTFLAGS="--cfg=fuzzing" cargo build`

Change-Id: If7a4091a67bc119ae06d576fe9d6f410759c8f9f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2616038
Tested-by: Keiichi Watanabe <815e4e8f7c92a23424d7c3f51ead622bcedbc720@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Auto-Submit: Keiichi Watanabe <815e4e8f7c92a23424d7c3f51ead622bcedbc720@chromium.org>
Reviewed-by: Chirantan Ekbote <35787c0e27de5c48735e07f8324823b765e8bcbc@chromium.org>
Commit-Queue: Keiichi Watanabe <815e4e8f7c92a23424d7c3f51ead622bcedbc720@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm