Do not run clean in cibuild

script/cibuild

@@ -53,8 +53,6 @@ def main():
   if PLATFORM == 'linux':
     os.environ['DISPLAY'] = ':99.0'
 
-  run_script('clean.py')
-
   # CI's npm is not reliable.
   npm = 'npm.cmd' if PLATFORM == 'win32' else 'npm'
   execute([npm, 'install', 'npm@2.12.1'])
@@ -81,8 +79,6 @@ def main():
     if PLATFORM != 'win32' and target_arch == 'x64':
       run_script('test.py', ['--ci'])
 
-  run_script('clean.py')
-
 
 def run_script(script, args=[]):
   sys.stderr.write('\nRunning ' + script +'\n')