org-agenda: Switch to current API for two calendar calls

* lisp/org-agenda.el (org-agenda-phases-of-moon, org-agenda-holidays):
  Update to use the current API

This commit fixes the display of holidays in the agenda for emacs 25.

Further for getting the lunar phases the usage of an obsolete alias
has been replaced by the current name.

lisp/org-agenda.el

@@ -9530,12 +9530,12 @@ entries in that Org-mode file."
 (defun org-agenda-phases-of-moon ()
   "Display the phases of the moon for the 3 months around the cursor date."
   (interactive)
-  (org-agenda-execute-calendar-command 'calendar-phases-of-moon))
+  (org-agenda-execute-calendar-command 'calendar-lunar-phases))
 
 (defun org-agenda-holidays ()
   "Display the holidays for the 3 months around the cursor date."
   (interactive)
-  (org-agenda-execute-calendar-command 'list-calendar-holidays))
+  (org-agenda-execute-calendar-command 'calendar-list-holidays))
 
 (defvar calendar-longitude)      ; defined in calendar.el
 (defvar calendar-latitude)       ; defined in calendar.el