diff --git a/master.cfg b/master.cfg
index 9202f5f..7b1b618 100644
--- a/master.cfg
+++ b/master.cfg
@@ -32,7 +32,6 @@ from sumfiles import DejaResults, set_web_base
 import os.path
 import urllib
 from json import load
-import random
 import re
 
 ####################################
@@ -806,6 +805,11 @@ class RunTestGDBPlainAIX (RunTestGDBAIX_Common, RunTestGDBPlain_c64t64):
 # All branches that are going to be watched.
 all_gdb_filter = ChangeFilter (branch_fn = should_watch_branch)
 
+# This function prevents a builder to build more than one build at the
+# same time.  This is needed because we do not have a way to lock the
+# git repository containing the test results of the builder, so
+# simultaneous builds can cause a mess when committing the test
+# results.
 def DefaultGDBCanStartBuild (builder, buildslave, buildrequest):
     return not builder.building
 
@@ -816,6 +820,8 @@ def DefaultGDBfileIsImportant (change):
 changes to build on GDB."""
     only_changelog = True
 
+    # Do not build the 'GDB Administrator' commits, that are used to
+    # increment the date on some files.
     if 'GDB Administrator' in change.who:
         return False
 
@@ -823,6 +829,7 @@ changes to build on GDB."""
     for filename in change.files:
         if 'ChangeLog' not in filename:
             only_changelog = False
+            break
 
     if only_changelog:
         return False
@@ -847,14 +854,11 @@ def load_config (c):
     config = load (open ("lib/config.json"))
     passwd = load (open ("lib/passwords.json"))
 
-    random.seed ()
-
     c['slaves'] = [BuildSlave (slave['name'], passwd[slave['name']],
                                max_builds = 1,
                                notify_on_missing = [ str (slave['admin']) ],
                                missing_timeout = 300,
-                               properties = { 'jobs' : slave['jobs'],
-                                              'randomWait' : "%d" % random.randrange (1, 30) })
+                               properties = { 'jobs' : slave['jobs'] }
                    for slave in config['slaves']]
 
     c['schedulers'] = []