Refactor InstanceIdentifier.create(Iterable)
This method is for things like binding/dom codec and similar users who
know what they are doing. Rename the method to 'unsafeOf()', so that the
compilation failures from the change in InstanceIdentifier.create(Class)'s
signature do not produce confusing guidance by pointing to this arcane
method.
Also document this method's purpose, with significant warning and update
it to take a List.
JIRA: MDSAL-730
Change-Id: I9def3750f16d87c11d12809e0f067daf0bf352b9
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>