Allow hgwebdir collections to follow symlinks.

Revert cfebb175704f, fixing the output of 2 tests

test-mv-cp-st-diff: avoid linkrev collisions The copy detection code relies heavily on the linkrevs, so it's better to avoid collisions in this test.

convert: avoid querying log of foreign svn branches Server configuration may prevent access to other branches, so don't even try to get them, instead of ignoring them afterwards.