configure: require libseccomp 2.2.0

The following patch is going to require TSYNC, which is only available
since libseccomp 2.2.0.

libseccomp 2.2.0 was released February 12, 2015.

According to repology, libseccomp version in different distros:

  RHEL-7: 2.3.1
  Debian (Stretch): 2.3.1
  OpenSUSE Leap 15: 2.3.2
  Ubuntu (Xenial):  2.3.1

This will drop support for -sandbox on:

  Debian (Jessie): 2.1.1 (but 2.2.3 in backports)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eduardo Otubo <otubo@redhat.com>