The change to do argument process before EAL init broke
the support of select-interface option. Fix by setting flag
and doing select-interface later.
Fixes: a8dde09f97df ("app/dumpcap: allow help/version without primary process")
Cc: stable@dpdk.org
Signed-off-by: Arshdeep Kaur <arshdeep.kaur@intel.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>