Revert r1550848. Instead of passing the responsibility to the caller we can
just handle the reparenting right before committing.

* subversion/include/svn_client.h
* subversion/libsvn_client/mtcc.c
* subversion/tests/libsvn_client/mtcc-test.c
  Revert anchor change behavior of r1550848.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1550938 13f79535-47bb-0310-9956-ffa450edef68