When breaking moves for a node as part of tree conflict resolving only break
its moves and the moves of its decendants, instead of also all
other unrelated shadowing moves at higher op-depths.

This resolves a case where a move from a specific path can be broken
multiple times, when multiple moves are layered over each other. Before this
patch that would trigger an sqlite constraint on the notify temporary table.

* subversion/libsvn_wc/wc-queries.sql
  (STMT_SELECT_MOVED_PAIR2): Rename query to...
  (STMT_SELECT_MOVED_PAIRS_DEPTH): ... this and update its behavior to match
    what its only user really needs.

* subversion/libsvn_wc/wc_db_update_move.c
  (break_moved_away_children_internal): Break moves only on the selected layer.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1538702 13f79535-47bb-0310-9956-ffa450edef68