Remove unused methods from cinder.utils

These methods and class  were left over from the split from Nova and are unused still.

Remove methods:
	debug()
	utf8()
	map_dict_keys()
	check_isinstance()
	timefunc()
	logging_error()
	temporary_mutation()
	generate_mac_address()

Remove class:
	UndoManager

Change-Id: Id3a94ff9066627b5c0efef068f8c569423f1e9d8
Merge "Remove unused methods from cinder.utils"