Bundle unpacking logic fails with tk-multi-setframerange

[th-pmacdonald]

tk-core/python/tank/util/zip.py

Lines 50 to 63 in b105eb0

	# - if the zip contains a single folder with all content inside,
	# assume the bundle is contained inside this structure. This is
	# a common scenario if a user has created a zip by right clicking on it
	# and selected 'create archive' or 'send to zip'.
	# compute number of unique root folders
	# note: zip module uses forward slash on all operating systems
	root_items = set(
	[item.split("/")[0] for item in zip_obj.namelist() if "/" in item]
	)
	# remove certain system items
	root_items -= SYSTEM_FILE_ITEMS
	if len(root_items) == 1:

If the toolkit bundle zip has only a single folder, then it unpacks that folder as the bundle, not the root of the zip.
This works for most packages, but for tk-multi-setframerange, this causes only the hooks folder being unpacked.

Suggested fix : Check for info.yml in the root folder as this is a clear indication of a shotgrid toolkit bundle.
Or check that if there is only a single folder, that there are no files in the root folder.