s4:drsuapi: don't return all linked attributes at the same time

s4:drsuapi: don't return all linked attributes at the same time

Windows gives them in chunks, but I don't know the correct
rule to calculate the chunk size.

For now I'll use 1500 as the max size.

Windows isn't happy when it gets ~ 100000 linked attributes in one
response. It corrupts its directory index and later moves some objects
to the LostAndFound folder.

metze