harvest_vmcore: replace regexp config parsing with augeas

    Replaces adhoc mtab and kdump.conf regexp parsing with
    an augeas implementation.

    Closes #770

Signed-off-by: Petr Kubat <pkubat@redhat.com>
spec: add python-augeas to the requires

Related to #770

Signed-off-by: Jakub Filak <jfilak@redhat.com>