sos: engine: collect more state file

Collect also:
    /var/lib/ovirt-engine/setup/answers
    /var/lib/ovirt-engine/external_truststore

Change-Id: I042343417e5b05da258b13eccea29cea65f46e44
Requires: http://gerrit.ovirt.org/18198
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>