org-agenda: Fix time regexp in org-get-entries-from-diary

* lisp/org-agenda.el (org-get-entries-from-diary): Make time regular
expression more precise.

Reported-by: Justin Abrahms <justin@abrah.ms>

lisp/org-agenda.el

@@ -5135,6 +5135,7 @@ of what a project is and how to check if it stuck, customize the variable
 	  (cons 'org-diary-default-entry diary-list-entries-hook))
 	 (diary-file-name-prefix nil) ; turn this feature off
 	 (diary-modify-entry-list-string-function 'org-modify-diary-entry-string)
+	 (diary-time-regexp (concat "^" diary-time-regexp))
 	 entries
 	 (org-disable-agenda-to-diary t))
     (save-excursion