xsddefault: Stop trying to parse 'temp_file' more than once

Instead we reuse the variable we've already parsed in the main
config parsing routine, which takes temp_path into account in a
somewhat clever manner, ensuring that we always have a tempfile
which we most likely can write to.

Signed-off-by: Andreas Ericsson <ae@op5.se>
xodtemplate: Clear the children map when creating servicedependencies

Otherwise we can't have more than one dependency from a single
service, or one that's been excluded from another servicedependency.

This went unnoticed in the wild for a long time and most likely would
have remained that way, as people generally tend to have each service
depend on only one other. With this patch the code seems to do what
it's supposed to though, which is block multiple service dependencies
from being created from the same object to the same object from a
single config object statement.

Objects galore there. Good thing at least I know what I mean...

Signed-off-by: Andreas Ericsson <ae@op5.se>