This commit adds a free() to null_auth_free_client_data, which plugs
the memory leak in maxinfo.
Also, this commit fixes some segfaults when multiple threads are
running status_row() or variable_row(). The functions use
statically allocated index variables, which often go out-of-bounds
in concurrent use. This fix changes the indexes to thread-specific
variables, with allocating and deallocating. This does seem to slow
the functions down somewhat.
de4ea067cf