Remove references to setuptools

Newer versions of cliff and stevedore use importlib rather than
setuptools to work with entry points. Replace any references to
"setuptools' entry points mechanism" with "Python's entry points
mechanism".

Change-Id: Iae36155685ee37ab5e38a0c173110a5ece33d05d
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

Author: stephenfin

doc/source/cli/commands.rst

@@ -306,7 +306,7 @@ Implementation
 --------------
 
 The command structure is designed to support seamless addition of plugin
-command modules via ``setuptools`` entry points.  The plugin commands must
+command modules via Python's *entry points* mechanism. The plugin commands must
 be subclasses of Cliff's ``command.Command`` object.  See :ref:`plugins` for
 more information.
 

doc/source/contributor/command-wrappers.rst

@@ -7,7 +7,7 @@ We do this with a message logged at WARNING level before any command output
 is emitted.
 
 OpenStackClient command classes are derived from the ``cliff`` classes.
-Cliff uses ``setuptools`` entry points for dispatching the parsed command
+Cliff uses Python's *entry points* mechanism for dispatching the parsed command
 to the respective handler classes.  This lends itself to modifying the
 command execution at run-time.
 

doc/source/contributor/plugins.rst

@@ -5,9 +5,8 @@ Plugins
 =======
 
 The OpenStackClient plugin system is designed so that the plugin need only be
-properly installed for OSC to find and use it.  It utilizes the
-``setuptools`` entry points mechanism to advertise to OSC the
-plugin module and supported commands.
+properly installed for OSC to find and use it. It utilizes Python's *entry
+points* mechanism to advertise to OSC the plugin module and supported commands.
 
 Adoption
 ========