Bugfix 43310903: acceptable version number

The Firefox validation tool ends with:

    Error: The minimum version that was specified is not an acceptable version number for the Mozilla product that it corresponds with.
    Version "14.0.1" isn't compatible with "firefox".
    Please check the list of valid versions at: https://addons.mozilla.org/en-US/firefox/pages/appversions/

which is the only blocking error for our extension.

The proposed modification is installable to FF 14.0.1 (cannot be installed with em:minVersion value set to '14.*') and passes the validation.