dissector: icmpv6: Fix yet another possible null pointer dereference

THe Coverity scanner discovered yet another possible null pointer
dereference. Fix it by checking the return value of pkt_pull().

Also remove some trailing whitespaces in the region.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
sock: Check return value of setsockopt() in set_tcp_nodelay()

Check the return value of setsockopt() and panic in case it is not 0, as
in the other setsockopt() wrapper functions.

This issue was discovered by the Coverity scanner.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
dissector: lldp: Rework capability printing

Make printing of capabilities a bit more intuitive by removing the
inline post-increment. This should also make the Coverity scanner happy
about this particular part.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>