Do you need to complete both routes indicated on a destination card?
You only have to make the required connection (Glasgow to France) once for 19 points. Like all destination tickets; a single ticket cannot be scored multiple times, even if you connect the locations via multiple routes. 

The reason that the ticket shows multiple routes is because France is a country, as opposed to a city. In the base Ticket to Ride game, destination tickets are only between two cities. But in this expansion, some of them include a country instead of a city. The country behaves differently because there are multiple spaces within that country. So instead of having to connect a specific place to another specific place; you just have to connect a specific place to one of those 2 places within France.

This is mentioned somewhat in the Ticket to Ride: Marklin rules:


  Some Destination Ticket include the name of a city and a country name. Each route leading to a country
  is a dead end and cannot be used to link two cities.