Fix position of buffer local variable declaration

'lexical-binding' should be declared first line of a file.

> If this buffer-local variable is non-nil, Emacs Lisp files and buffers are evaluated using lexical binding instead of dynamic binding. (However, special variables are still dynamically bound; see below.) If nil, dynamic binding is used for all local variables. This variable is typically set for a whole Emacs Lisp file, as a file local variable (see File Local Variables). Note that unlike other such variables, this one must be set in the first line of a file.

Last sentence says about this issue.

See also  http://www.gnu.org/software/emacs/manual/html_node/elisp/Using-Lexical-Binding.html.