tests/test-revert-flags.t

server: skip logging of ECONNRESET

I believe this was exposed by 5492dc20, because the sending of the 500
would have already failed and prevented this logging. On Python 3,
this will be a ConnectionResetError, which is a subtype of OSError,
which is why we check for both OSError and socket.error.

Bonus: this fixes a race in test-hgweb.t where sometimes the
ECONNRESET wouldn't happen, because now we just don't log those
errors.

Differential Revision: https://phab.mercurial-scm.org/D5764

#require execbit

  $ hg init repo
  $ cd repo
  $ echo foo > foo
  $ chmod 644 foo
  $ hg ci -qAm '644'

  $ chmod 755 foo
  $ hg ci -qAm '755'

reverting to rev 0

  $ hg revert -a -r 0
  reverting foo
  $ hg st
  M foo
  $ hg diff --git
  diff --git a/foo b/foo
  old mode 100755
  new mode 100644

  $ cd ..