Properly specify rsync --exclude directories

Using '--exclude=dirname/*' to explicitly specify directories whose contents
should not be copied. This will result in empty directories being created
on the destination if they exist on the source, but that's not a problem as
they are needed anyway.

Previously the generated rsync command contained '--exclude=pg_log*', which
will break replication on 9.5 as the wildcard expansion prevents the
'pg_logical' directory from being copied.