icalendar.el bug fix patch

[Rajeev Narang]

icalendar-export-region does not export multi-line Desc as it is imported by 
icalendar-import-file.  The following patch fixes the issue.  If acceptable, 
please commit. Thanks.

diff --git a/lisp/calendar/icalendar.el b/lisp/calendar/icalendar.el
index 1186ced3fb..1f4e582aa5 100644
--- a/lisp/calendar/icalendar.el
+++ b/lisp/calendar/icalendar.el
@@ -1244,7 +1244,7 @@ icalendar--parse-summary-and-rest
                      (concat "\\(" icalendar-import-format-uid "\\)??"))))
        ;; Need the \' regexp in order to detect multi-line items
         (setq s (concat "\\`"
-                        (replace-regexp-in-string "%s" "\\(.*?\\)" s nil t)
+                        (replace-regexp-in-string "%s" "\\([^z-a]*?\\)" s nil 
t)
                         "\\'"))
         (if (string-match s summary-and-rest)
             (let (cla des loc org sta url uid) ;; sum