Improve idrop deploy.

* Case insensitive matching for desktop idrop links.
* Remove /opt/irodsidrop directory if it exists.

	modified:   init_files/v2/atmo_init_full.py
Merge branch 'abyssinian-nightjar' of github.com:iPlantCollaborativeOpenSource/atmosphere into abyssinian-nightjar
Prevent exception when monitor_instances_for_user runs with a user that may not exist.
	modified:   service/tasks/allocation.py
PEP8 Compliance.
	modified:   api/project.py
Add logging if core_instance is missing on delete.
	modified:   api/instance.py
Default to warn for dependency logging.
	modified:   atmosphere/settings/__init__.py
PEP8 Compliance.
	modified:   core/models/project.py
Fix problem with deleted and end_dated elements appearing in project list.

only_current = Q(end_date=None) | Q(end_date__gt=timezone.now())
This was not working as intended. There must be a bug. It's difficult
to reproduce but it doesn't always work. Instead it needs to be built up from
an empty Q(). This seems to fix it for now.

	modified:   api/project.py
Merge branch 'abyssinian-nightjar' of github.com:iPlantCollaborativeOpenSource/atmosphere into abyssinian-nightjar