examples/var_service: use "exec sleep 5" instead of "{ sleep 5; exit; }"

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

examples/var_service/dhcp_if/run

@@ -8,7 +8,7 @@ pwd="$PWD"
 if="${PWD##*/dhcp_}"
 
 echo "* Upping iface $if"
-ip link set dev "$if" up || { sleep 5; exit; }
+ip link set dev "$if" up || exec sleep 5
 
 echo "* Starting udhcpc on $if [$$]"
 exec \