org.el: (org-get-cursor-date): Fix regular expression

* lisp/org.el (org-get-cursor-date): Fix regular expression.

Previous regular expression assumed the time grid string will have two
digits in the hour portion of the time string.  However, the time grid
string does not always have two digits.  For example:

" 8:00......"

lisp/org.el

@@ -19064,7 +19064,7 @@ earliest time on the cursor date that Org treats as that date
   (let (date day defd tp hod mod)
     (when with-time
       (setq tp (get-text-property (point) 'time))
-      (when (and tp (string-match "\\([0-9][0-9]\\):\\([0-9][0-9]\\)" tp))
+      (when (and tp (string-match "\\([0-2]?[0-9]\\):\\([0-5][0-9]\\)" tp))
 	(setq hod (string-to-number (match-string 1 tp))
 	      mod (string-to-number (match-string 2 tp))))
       (or tp (let ((now (decode-time)))