Merge patch from Jeremy Fitzhardinge:

13-fix-printf
  Fix stupid bug I introduced into printf with 14-sprintf.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@1261 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/vg_mylibc.c b/coregrind/vg_mylibc.c
index 38af87a..75dedbc 100644
--- a/coregrind/vg_mylibc.c
+++ b/coregrind/vg_mylibc.c
@@ -652,7 +652,7 @@
 
    if (n_myprintf_buf > 0 && VG_(clo_logfile_fd) >= 0)
       VG_(write)
-         ( VG_(clo_logfile_fd), myprintf_buf, ret);
+         ( VG_(clo_logfile_fd), myprintf_buf, n_myprintf_buf);
 
    va_end(vargs);