[PATCH] svn_client_list4: accept `NULL` patterns

Hi,

while continuing my work on the obstructed checkout patch I just
updated to the new `svn_client_list4` call, which introduced a
new `patterns` parameter. I initially run into a `NULL` pointer
derefeernce, as I expected that the patterns parameter may also
be `NULL`, as it is often the case for parameters which are not
in use.

The attached patch changes the function to accept a `NULL`
argument for `parameters` in addition to an empty array, which is
mostly a convenience/consistency thing for callers of the new
function.

Regards
Patrick

[[[
svn_client_list4: accept `NULL` patterns

The recently introduced `svn_client_list4` introduced a new
parameter `patterns`, which can be used to filter listed paths.
When an empty pattern array is passed to the function, all paths
are being reported.

In the case where a caller does not want to filter the list,
he first has to create an empty array. Improve usability by also
allowing a caller to pass in a `NULL` pointer instead of an empty
array.

* subversion/libsvn_repos/list.c:
  (matches_any): Return `TRUE` if `patterns` is `NULL`
]]]

-- 
Patrick Steinhardt, Entwickler
elego Software Solutions GmbH, http://www.elego.de
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