app: fix exit messages

app: fix exit messages

Some applications were printing useless messages with rte_exit()
after showing the help. Using exit() is enough in this case.

Some applications were using a redundant printf or fprintf() before
calling rte_exit(). The messages are unified in a single rte_exit().

Some rte_exit() calls were missing a line feed or returning a wrong code.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Wisam Jaddo <wisamm@nvidia.com>
Acked-by: Ori Kam <orika@nvidia.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: David Marchand <david.marchand@redhat.com>