Following up on r1558468, send output of the sqlite error logging (when
enabled) to the same output stream as SVN_DBG(); typically stdout.

* subversion/include/private/svn_sqlite.h
  (svn_sqlite__dbg_enable_errorlog): Update documentation.

* subversion/libsvn_subr/sqlite.c
  (sqlite_error_log): Update implementation.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1558907 13f79535-47bb-0310-9956-ffa450edef68