We don't need it. Every series import is independent of the other. This
is intentional as the branches may change over a package rename; yet the
queue sync operation is still well-defined in this case.
We cannot use GitUbuntuSourceInformation because to construct one needs
a source package name, and when we start the loop we do not have one.
However, we do have an lp object and can simply retrieve all current
series names from there.
Further, we do actually want to include the development series, since
NEW packages may need processing from there, so we also drop the
"stable" filter.
fetch_base_remotes() requires an argument called must_exist, so set it.
For now, we assume must_exist=True. In the future it makes sense for
queue handling to work even without an existing repository, for example
in the case of NEW. But for the moment we can get things working
without.
We only need 'HEAD' in the current code to extract the source package
name, but we don't actually use that value (and/or we assume that value
is consistent across all the devel branches). Rather than implicitly
assume that, actually check that is true, but also use the first devel
branch's source package as the initial value to compare against.
At some point in the future, we can make queue sync more flexible to
handle a repository with multiple source packages locally, but that
would require some refactoring of our code (e.g., namespacing the
remotes by source package name).
