[PATCH] Conversion func for translating svn_wc_status3_t to svn_wc_status2_t

Hi!

I'm letting the func return the old struct in the same manner as
svn_wc__cd2_to_cd() works for conflict_description_t. When we start
replacing entries, we might need to return and error instead, but since
the func will only be used in two places I can easily change parameters
and return values then.

[[[
Follow-up to r932571. Since converting a svn_wc_status3_t struct to a
svn_wc_status2_t dito will be a pretty complex operation, we create a
function to handle it.

* subversion/include/private/svn_wc_private.h
  (svn_wc__status2_from_3): New.

* subversion/libsvn_wc/util.c
  (svn_wc__status2_from_3): New.

* subversion/libsvn_wc/deprecated.c
  (status4_wrapper_func): Call the new func.

* subversion/libsvn_client/deprecated.c
  (status4_wrapper_func): Call the new func.

Suggested by: gstein
]]]