sandbox: missing return value checks in eth-raw-os

We should check the return value of fcntl().

Addresses-Coverity-ID: 131108 ("Unchecked return value from library")
Addresses-Coverity-ID: 131109 ("Unchecked return value from library")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
1 file changed