Revert r1804673, r1804672 and r1803144 which made "svn import" stream deltas without creating temporary files over HTTP.
There is a better (simpler and less invasive) solution that involves using resettable streams, instead of implementing an open txdelta callback that always creates a new stream. That is what I'll try to do.
The shortlog of the reverted changesets is:
r1803144: Stream svndiff deltas without creating temporary files during 'svn import' over HTTP.
r1804672: Fix an oversight in the txdelta_next_window adapter used when importing files over HTTP.
r1804673: Rewrite the txdelta_next_window() function using a local variable.