SU - add syscache for DIRECTORY and permission checks to COPY

COPY Permission Checks
 - Superuser is always allowed to bypass permission checks. If the user
   is not a superuser then permission checks are applied.
 - A directory entry must exist for the parent directory of the output/input
   file.  If an entry does not exist then an error is raised.
 - Directory ACL is checked for user.  If insufficient permissions then
   an error is raised.
 - Checks are applied to both COPY FROM and COPY TO.
 - All other conditions for a COPY are preserved.