refactorize: reflect recent changes in map_string_t

Related to abrt/libreport#147

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>
bodhi, retrace: support /etc/os-release

Related to abrt/libreport#147

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