Fix special case in file comparison code posted here:
http://svn.haxx.se/dev/archive-2011-02/0392.shtml

* subversion/libsvn_subr/io.c
  (contents_identical_p): handle special case

Found by: danielsh

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/integrate-io-improvements@1072297 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/subversion/libsvn_subr/io.c b/subversion/libsvn_subr/io.c
index 5d9e6e9..e87bb2d 100644
--- a/subversion/libsvn_subr/io.c
+++ b/subversion/libsvn_subr/io.c
@@ -3831,6 +3831,11 @@
         }
     }
 
+  /* Special case: one file being a prefix of the other and the shorter
+   * file's size is a multiple of SVN__STREAM_CHUNK_SIZE. */
+  if (!err && (eof1 != eof2))
+    *identical_p = FALSE;
+
   return svn_error_return(
            svn_error_compose_create(
                 err,