Move the write check for propsets to before the node walker, rather than for every node in the node walker.  Add an explanitory comment as to why this is possible.
Move the write check for propsets to before the node walker, rather than
for every node in the node walker.  Add an explanitory comment as to why this
is possible.

* subversion/libsvn_wc/props.c
  (do_propset): Remove write check.
  (svn_wc_prop_set4): Move the write check here, add comment.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1096490 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion