eudev: fix error handling init script

Replace (echo "msg" && exit 1) by { echo "msg"; exit 1; }.

The (list) compound command runs in a subshell, so the "exit" interrupts
the subshell, not the main script. Examples:

    $ sh -c "echo 1; (exit 1); echo 2"
    1
    2
    $ sh -c "echo 1; { exit 1; }; echo 2"
    1
    $

Signed-off-by: Carlos Santos <casantos@datacom.ind.br>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>