add a sleep to the test to fix a race condition

mail/sympl/test.d/tc_exim4.rb

@@ -406,6 +406,7 @@ class Exim4ConfigTest < Test::Unit::TestCase
     do_acl_script('exim4_acl_tests/antivirus_accept')
 
     FileUtils.touch(File.join(config_dir, "antivirus"))
+    sleep 3
     # OK the file is there now, so reject (as per default)
     do_acl_script('exim4_acl_tests/antivirus_reject')