contrib/linux-wheel-centos5-blacklist

httppeer: refactor how httppeer is created (API)

Previously, we passed a bunch of arguments to httppeer.__init__,
validated them, then possibly constructed a valid instance.

A short while ago, we refactored sshpeer so all the validation and
setup work occurs before the constructor. We introduced a makepeer()
to hold most of this logic.

This commit gives httppeer the same treatment.

As a sign that the previous design was poor, __del__ no longer
conditionally checks for the presence of an attribute that may
not be defined (it is always defined in the new code).

.. api::

   httppeer.httppeer.__init__ now takes additional arguments.
   Instances should be obtained by calling httppeer.instance()
   or httppeer.makepeer() instead.

Differential Revision: https://phab.mercurial-scm.org/D2725

test-convert-git.t
test-subrepo-git.t
test-patchbomb-tls.t