tests: rm/ext3-perf: relax this test

* tests/rm/ext3-perf: If set-up takes too long, use the set-up time
as the removal time limit.  Otherwise, a parallel "make check" would
usually fail when run with RUN_VERY_EXPENSIVE_TESTS=yes.

tests/rm/ext3-perf

@@ -1,7 +1,7 @@
 #!/bin/sh
 # ensure that "rm -rf DIR-with-many-entries" is not O(N^2)
 
-# Copyright (C) 2008 Free Software Foundation, Inc.
+# Copyright (C) 2008-2009 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -67,6 +67,11 @@ test $ok = 1 || framework_failure
 setup_duration=$(expr $(date +%s) - $start)
 echo creating a $n-entry directory took $setup_duration seconds
 
+# If set-up took longer than the default $threshold_seconds,
+# use the longer set-up duration as the limit.
+test $threshold_seconds -lt $setup_duration \
+  threshold_seconds=$setup_duration
+
 fail=0
 start=$(date +%s)
 timeout ${threshold_seconds}s rm -rf d; err=$?