[Checkins] [zopefoundation/Products.ZSQLMethods] bbdb64: Fix how we join a transaction.

[Viktor Dick]

  Branch: refs/heads/transaction-management
  Home:   https://github.com/zopefoundation/Products.ZSQLMethods
  Commit: bbdb64eaaf569716b5492e280f0383ec33ef52d5
      https://github.com/zopefoundation/Products.ZSQLMethods/commit/bbdb64eaaf569716b5492e280f0383ec33ef52d5
  Author: Viktor Dick <viktor.dick at perfact.de>
  Date:   2020-02-23 (Sun, 23 Feb 2020)

  Changed paths:
    M src/Shared/DC/ZRDB/TM.py

  Log Message:
  -----------
  Fix how we join a transaction.

ITransaction no longer has a method register(), the intended way to
register a component in the current transaction seems to be join(). This
does not immediately fail due to the unqualified except clause that
hides this error, but the effect is that TM objects are no longer
correctly rolled back on transaction abort.