Plugin autogen list: handle variable-width plugin names

We've had a couple of cases where plugin names are longer than our
table width.

Take the fixed-with table-header out of the header file, and generate
it dynamically based on first-column width.  To simplify, take
advantage that RST allows a variable-length last column and so don't
specify it's width.

Add a link to the cgit URL for each project you can click on to browse
the source (link text remains the git:// URL).

Add some logging so you can see what the python generator is doing,
should you run it.

Change-Id: I5d5e692039bbb30b2508119412472dac1d105c08
diff --git a/tools/generate-devstack-plugins-list.py b/tools/generate-devstack-plugins-list.py
index 1fa5501..aeec4dd 100644
--- a/tools/generate-devstack-plugins-list.py
+++ b/tools/generate-devstack-plugins-list.py
@@ -23,9 +23,12 @@
 #     working directory
 #   * network access to https://git.openstack.org/cgit
 
+import logging
 import json
 import requests
 
+logging.basicConfig(level=logging.DEBUG)
+
 url = 'https://review.openstack.org/projects/'
 
 # This is what a project looks like
@@ -37,6 +40,8 @@
 '''
 
 def is_in_openstack_namespace(proj):
+    # only interested in openstack namespace (e.g. not retired
+    # stackforge, etc)
     return proj.startswith('openstack/')
 
 # Rather than returning a 404 for a nonexistent file, cgit delivers a
@@ -50,10 +55,13 @@
     else:
         False
 
+logging.debug("Getting project list from %s" % url)
 r = requests.get(url)
 projects = sorted(filter(is_in_openstack_namespace, json.loads(r.text[4:])))
+logging.debug("Found %d projects" % len(projects))
 
 found_plugins = filter(has_devstack_plugin, projects)
 
 for project in found_plugins:
+    # strip of openstack/
     print project[10:]