Fix the help text process and the generated wrong help

The wrong help text of bash-completion is generated by the process of
choosing first line from the source code comment. We should get the all
help text from the source code comment, and use it.

So this commit removes this unnecessary process, and also fix the
README.rst for proper help text.

Fixes bug 1206005

Change-Id: Id4f5b6a7722197f09eb366ba8f3e643e1af91805

README.rst

@@ -198,7 +198,8 @@ You'll find complete documentation on the shell by running
         x509-create-cert    Create x509 cert for a user in tenant
         x509-get-root-cert  Fetches the x509 root cert.
         bash-completion     Prints all of the commands and options to stdout so
-                            that the
+                            that the nova.bash_completion script doesn't have to
+                            hard code them.
         help                Display help about this program or one of its
                             subcommands.
 

novaclient/shell.py

@@ -469,7 +469,7 @@ class OpenStackComputeShell(object):
             command = attr[3:].replace('_', '-')
             callback = getattr(actions_module, attr)
             desc = callback.__doc__ or ''
-            action_help = desc.strip().split('\n')[0]
+            action_help = desc.strip()
             arguments = getattr(callback, 'arguments', [])
 
             subparser = subparsers.add_parser(command,