build: fix missing tool name in 'configure --help' output

Change-Id: I00a106c6a8c4c6ebbbfcf1a0db1ad98a66af18f6
diff --git a/tools/wscript b/tools/wscript
index 12954aa..b93eb8f 100644
--- a/tools/wscript
+++ b/tools/wscript
@@ -1,18 +1,18 @@
 # -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 top = '..'
 
-from waflib import Options, Logs, Errors
+from waflib import Options, Errors
 
 def options(opt):
     for subdir in opt.path.ant_glob(['*'], dir=True, src=False):
         opt.add_option('--enable-%s' % subdir,
                    help='Build tool %s, enabled by default' % subdir,
-                   action="store_true",
+                   action='store_true',
                    dest='enable_%s' % subdir)
 
         opt.add_option('--disable-%s' % subdir,
-                   help='Do not build tool %s',
-                   action="store_true",
+                   help='Do not build tool %s' % subdir,
+                   action='store_true',
                    dest='disable_%s' % subdir)
 
         opt.recurse(str(subdir), mandatory=False)