Don't assume that every node that has a record in a single-db database is a working copy root. This resolves the regression that you can't checkout a new working copy over a deleted node in single-db. (So this fixes copy_tests.py 21 for single-db).
Before this patch the wc-db did a simple check to see if a row existed for the directory node, but this is not the task of the wc-db layer (which should just return the relevant wcroot info for a working copy).
This patch moves this check to svn_wc__internal_check_wc().
* subversion/libsvn_wc/adm_files.c (svn_wc__internal_ensure_adm): Update caller. Passing TRUE here fixes copy-tests.py 21 for us.
* subversion/libsvn_wc/lock.c (svn_wc__internal_check_wc): In single-db mode, verify if the directory is really part of the wc-ng working copy, or if it just some node below a wcroot. (svn_wc_check_wc2): Update caller, passing false for compatibility with before this patch. Add todo marker. (probe, open_single): Update callers, passing FALSE to allow locking missing nodes.