org-clock: Fix CLOCK_INTO_DRAWER property check

* lisp/org-clock.el (org-clock-into-drawer): Fix processing of
properties so that they can override global value.

Previously, if the 'CLOCK_INTO_DRAWER' or 'LOG_INTO_DRAWER' property was
nil, the local property setting would not override the global
variable [1]. These changes make the behavior match the docstring
description ('CLOCK_INTO_DRAWER' and 'LOG_INTO_DRAWER' properties
override `org-clock-into-drawer', with 'CLOCK_INTO_DRAWER' given
precedence).

[1] http://stackoverflow.com/questions/26405415/how-to-locally-unset-org-clock-into-drawer-t

TINYCHANGE

lisp/org-clock.el

@@ -74,13 +74,15 @@ if the current entry has or inherits a LOG_INTO_DRAWER property,
 it will be used instead of the default value.
 The default is the value of the customizable variable `org-clock-into-drawer',
 which see."
-  (let ((p (org-entry-get nil "CLOCK_INTO_DRAWER" 'inherit))
-	(q (org-entry-get nil "LOG_INTO_DRAWER" 'inherit)))
-    (cond
-     ((or (not (or p q)) (equal p "nil") (equal q "nil")) org-clock-into-drawer)
-     ((or (equal p "t") (equal q "t")) "LOGBOOK")
-     ((not p) q)
-     (t p))))
+  (let ((p (org-entry-get nil "CLOCK_INTO_DRAWER" 'inherit t))
+        (q (org-entry-get nil "LOG_INTO_DRAWER" 'inherit t)))
+    (cond ((equal p "nil") nil)
+          ((equal p "t") t)
+          (p)
+          ((equal q "nil") nil)
+          ((equal q "t") t)
+          (q)
+          (t org-clock-into-drawer))))
 
 (defcustom org-clock-out-when-done t
   "When non-nil, clock will be stopped when the clocked entry is marked DONE.