netsniff-ng: Remove unnecessary initialization of struct ctx members

These will be set later on depending on command line option (or panic()
out) and they're set to 0 by init_ctx() anyways.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
netsniff-ng: Remove unnecessary memset of struct pollfd

rx_poll will be passed to prepare_polling() which already zeros the
struct, so no need to do it before.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
trafgen: Remove unnecessary initialization of ct.reserve_size

It will be set later on depending on command line option (or panic()
out) and it is initialized to 0 by a memset() before anyways.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Merge remote-tracking branch 'upstream/master'