Fixed disabling of expired images

The same as with creating new ones, `chown` and `chgrp` should be
done separately.
Fixed parsing existing image templates

Just a temporary fix, only the first ID element should be used.
XML handling should be updated and streamlined in general.
Fixed logging in DisableExpiredImageID()
Fixed parsing existing image templates, pt. 2
Added error logging to HandleAvailablePostfix()
Bumped forgotten handler version
Fixed logging method (warn -> warning)
Merge pull request #5 from arax/dis_fix

Various fixes for logging and chown/chgrp