Simplify loop construction. No functional changes.

* subversion/libsvn_wc/wc_db_private.h
  (svn_wc__db_op_depth_moved_to): Move documentation here.

* subversion/libsvn_wc/wc_db.c
  (svn_wc__db_op_depth_moved_to): Move documentation to header.
    Verify precondition. Remove duplicated loop condition by adding
    explicit break.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1530871 13f79535-47bb-0310-9956-ffa450edef68