* lisp/org: Fix some compiler warnings

* lisp/org: Fix some compiler warnings

* lisp/org/ob-core.el (org-babel-check-confirm-evaluate)
(org-babel-map-src-blocks): Don't emit warnings if added vars are not used.
(*this*): Declare as dyn-bound.
(org-babel-expand-src-block, org-babel-load-in-session)
(org-babel-switch-to-session-with-code, org-babel-get-rownames):
Mark unused args.
(org-babel-combine-header-arg-lists): Remove unused var `args'.
(org-babel-find-named-block): Remove unused var `msg'.

* lisp/org/org-src.el (org-inhibit-startup, org-src-fontify-natively):
Declare as dyn-bound.
(org-edit-src-code): Remove unused var `lfmt'.
(org-edit-fixed-width-region): Remove unused var `preserve-indentation'.