LaTeX export: Make quotes exported right before a footnote reference.

LaTeX export:  Make quotes exported right before a footnote reference.

Matt Lundin writes:

    I'm have a *minor* issue to report. It occurs when I export
    an org file with footnotes to LaTeX. Specifically, it has to
    do with the combination of American style quotation marks
    and footnotes.

    According to many American manuals of style, quotation marks
    are to be placed after a sentence ending period if the
    quoted passage is at the end of the sentence. E.g.

    ,----
    | Here is "a quote."
    |
    | not
    |
    | Here is "a quote".
    `----

    When I use American style quotation in conjuction with a
    footnote, the exporter does not convert the closing quote
    marks into a two single quotation marks (i.e., LaTeX smart
    quotes).

    Thus, the following source snippet:

    ,----
    | This is a footnote "with a quote."[fn:sample] And here
    |  is another footnote "with a quote".[fn:another]
    |
    | [fn:sample] Here is the sample footnote.
    |
    | [fn:another] Another footnote.
    `----

    Becomes

    ,----
    | This is a footnote ``with a quote."\footnote{Here is
    |    the sample footnote. } And here is another footnote ``with
    |  a quote''.\footnote{Another footnote. }
    `----

    Notice the double quotation mark (rather than two single
    apostrophes) at the end of the first sentence. Notice also
    the correct quotation mark format appears in the second
    sentence, where the period comes after the quotation mark.

This commit addresses this issue by checking of text
protection is off not after the quotation mark, but before.