Finish the working copy version compatibility work started in r7661:
* subversion/libsvn_wc/lock.c
(maybe_upgrade_format): Renamed from upgrade_format, filled in.
(create_lock): Don't call upgrade_format, we don't have the
lock->wc_format yet. Instead, callers of create_lock will have
to call maybe_upgrade_format.
(do_open, svn_wc__adm_steal_write_lock): Call maybe_upgrade_format.
* subversion/include/svn_error_codes.h
(SVN_ERR_WC_FORMAT_UPGRADE): New error code.
git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/partial-authz-dev@847746 13f79535-47bb-0310-9956-ffa450edef68