Nightly test changes:

- Put the old tree in valgrind-old/ and the new one in valgrind-new/,
  instead of using valgrind/ for both.  That way, the old tree is still
  present after running the tests, so it can be inspected for problems.

  This required changing how ABT_RUN_REGTEST worked -- it no longer should
  change directories itself -- but I think Bart's machine is the only one
  using that and I updated the .conf file accordingly.

- Change some variable names -- only use the "ABT_" prefix for variables
  defined in the .conf files, and use $DIR and $TAG to match the README.txt.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@10248 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/nightly/README.txt b/nightly/README.txt
index 86a4d92..204f359 100644
--- a/nightly/README.txt
+++ b/nightly/README.txt
@@ -156,9 +156,9 @@
 - $DIR/sendmail.log contains the output (stdout and stderr) from
   $DIR/conf/$TAG.sendmail goes in $DIR/sendmail.log.  
 
-- $DIR/valgrind/ contains the tested tree (and $DIR/valgrind/Inst/ contains
-  the installed code).  It is used for both trees and so after the tests
-  have completed it will contain the newer tree.
+- $DIR/valgrind-old/ and $DIR/valgrind-new/ contain the tested trees (and
+  $DIR/valgrind-old/Inst/ and $DIR/valgrind-new/Inst/ contain the installed
+  code).
 
 If the tests aren't run, the following file is produced: