Fix bug with #+BIND during LaTeX export

Fix bug with #+BIND during LaTeX export

Christopher Suckling writes:

> Thank you, but not quite working yet:
>
> ,----
> | #+BIND: org-export-latex-title-command ""
> `----
>
> now appears to be having the *effect* of setting a global variable.
>
> I load Emacs then visit the below test org file. I then export the file.
>
> I get a \maketitle line.
>
> I then C-c C-c on the #+BIND: line and re-export.
>
> \maketitle is removed.
>
> I then export another org file without the #+BIND: line.
>
> There is no \maketitle, even though there should be.
>
> I add
>
> ,----
> | #+BIND: org-export-latex-title-command "\foobar"
> `----
>
> to the new org file, C-c C-c and export:
>
> \foobar is added to the exported file.
>
> Finally, I re-export the original test org file (without C-c C-c on the
> #+BIND: line):
>
> \foobar is added to the exported file.
>
> However,
>
> ,----
> | C-h v org-export-latex-title-command
> `----
>
> always returns the value "\\maketitle", no matter what the value of the
> #+BIND: line.
>
> Best, Christopher