Remove unnecessary invocations of org-mode

* lisp/ox-publish.el: (org-publish-find-title) (org-publish-find-date)
  Fix unnecessary invocations of org-mode with
  org-inhibit-startup.

The functions above call org-mode with org-inhibit-startup in org
buffers that are already open. The result is that these open buffers
lose some crucial local variables during publishing. For instance,
an open buffer will lose its dir-local-variables-alist setting
during publishing. There is no need to call org-mode here, because
org-mode is a) either already initialized in the buffer or b)
initialized via earlier call to find-file-no-select.

This looks to me like a relic of some past time when these functions were
called in temporary buffers that contained copies of the file's contents.

lisp/ox-publish.el

@@ -801,11 +801,9 @@ Default for SITEMAP-FILENAME is 'sitemap.org'."
   "Find the title of FILE in project."
   (or
    (and (not reset) (org-publish-cache-get-file-property file :title nil t))
-   (let* ((org-inhibit-startup t)
-	  (visiting (find-buffer-visiting file))
+   (let* ((visiting (find-buffer-visiting file))
 	  (buffer (or visiting (find-file-noselect file))))
      (with-current-buffer buffer
-       (org-mode)
        (let ((title
 	      (let ((property (plist-get (org-export-get-environment) :title)))
 		(if property
@@ -826,7 +824,6 @@ time in `current-time' format."
 	   (file-buf (or visiting (find-file-noselect file nil)))
 	   (date (plist-get
 		  (with-current-buffer file-buf
-		    (let ((org-inhibit-startup t)) (org-mode))
 		    (org-export-get-environment))
 		  :date)))
       (unless visiting (kill-buffer file-buf))