[O] org-jira.el updated

[Bao Haojun]

Hi, all

I have updated the org-jira.el as suggested by Bastien and Richard
Riley:

- Renamed jira2 to jiralib, to avoid confusion with the '2' and add the
  note that it is a library (I looked to merge with jira.el, but backed
  off as I myself do not use jira-mode).

- Fixed a bug for emacs version < 23 when login.

- Merged the jira link type by Jonathan Arkell.

As a result, a minor change to installation in .emacs (emacswiki
updated):

#+begin_src emacs-lisp
(setq jiralib-url "http://jira-host";)
(require 'org-jira) ;jiralib is not explicitly required, since org-jira will 
load it
#+end_src

-- 
All the best

 Bao Haojun