Fix setup.py for chmod data files.

setup.py

@@ -113,7 +113,7 @@ class install_man( install_data ) :
         install_data.finalize_options(self)
         for root,dirs,files in os.walk(BUILD_MAN_PATH):
             for filename in files:
-                self.data_files += [(path.join(self.install_dir,root[6:]),
+                self.data_files = [(path.join(self.install_dir,root[6:]),
                                     [path.join(root,filename)])]
 
 class cl_install_data(install_data):
@@ -147,7 +147,6 @@ class cl_install_data(install_data):
                 if flagFound:
                     os.chmod(path, mode)
 
-
 class install(distutils.command.install.install):
     def has_man(self):
         return len(glob.glob("build/man/*")) > 0