Fix typo

* lisp/org.el (org-check-before-date):
(org-check-after-date):
(org-check-dates-range): Fix typo.

Reported-by: Michael Strey <mstrey@strey.biz>
<http://permalink.gmane.org/gmane.emacs.orgmode/98094>

lisp/org.el

@@ -17415,7 +17415,7 @@ both scheduled and deadline timestamps."
 	(callback
 	 `(lambda ()
 	    (and ,(if (memq org-ts-type '(active inactive all))
-		      '(eq (org-element-type (org-element-context) 'timestamp))
+		      '(eq (org-element-type (org-element-context)) 'timestamp)
 		    '(org-at-planning-p))
 		 (time-less-p
 		  (org-time-string-to-time (match-string 1))
@@ -17431,7 +17431,7 @@ both scheduled and deadline timestamps."
 	(callback
 	 `(lambda ()
 	    (and ,(if (memq org-ts-type '(active inactive all))
-		      '(eq (org-element-type (org-element-context) 'timestamp))
+		      '(eq (org-element-type (org-element-context)) 'timestamp)
 		    '(org-at-planning-p))
 		 (not (time-less-p
 		       (org-time-string-to-time (match-string 1))
@@ -17450,7 +17450,7 @@ both scheduled and deadline timestamps."
 	    (let ((match (match-string 1)))
 	      (and
 	       ,(if (memq org-ts-type '(active inactive all))
-		    '(eq (org-element-type (org-element-context) 'timestamp))
+		    '(eq (org-element-type (org-element-context)) 'timestamp)
 		  '(org-at-planning-p))
 	       (not (time-less-p
 		     (org-time-string-to-time match)