Remove links to our old Open edX courses (#1625)

Author: julienrf

learn.md

@@ -11,24 +11,18 @@ redirect_from:
 ## Online Courses from EPFL
 
 The following courses are available for free. They teach you the main features of the Scala language and introduce you
-to functional programming. They are published on both [Coursera](https://www.coursera.org) and edX (either on an
-EPFL-hosted Open edX instance at [courseware.epfl.ch](https://courseware.epfl.ch/), or on
-[www.edx.org](https://www.edx.org)).
+to functional programming. They are published either on [Coursera](https://www.coursera.org) or [edX](https://www.edx.org).
 
- * Functional Programming in Scala Specialization (on [Coursera](https://www.coursera.org/specializations/scala)).
+ * [Functional Programming in Scala Specialization](https://www.coursera.org/specializations/scala).
    The Specialization provides a hands-on introduction to functional programming using Scala. You can access the courses
    material and exercises by either signing up for the specialization or auditing the courses individually. The
    specialization has the following courses.
-    * Functional Programming Principles in Scala ([Coursera](https://www.coursera.org/learn/progfun1) and
-      [Open edX](https://courseware.epfl.ch/courses/course-v1:EPFL+progfun1+2018_T1/about)),
-    * Functional Program Design in Scala ([Coursera](https://www.coursera.org/learn/progfun2) and
-      [Open edX](https://courseware.epfl.ch/courses/course-v1:EPFL+progfun2+2018_T1/about)),
-    * Parallel programming ([Coursera](https://www.coursera.org/learn/parprog1) and
-      [Open edX](https://courseware.epfl.ch/courses/course-v1:EPFL+parprog1+2018_T1/about)),
-    * Big Data Analysis with Scala and Spark ([Coursera](https://www.coursera.org/learn/scala-spark-big-data) and
-      [Open edX](https://courseware.epfl.ch/courses/course-v1:EPFL+scala-spark-big-data+2018-T1/about)),
-    * Functional Programming in Scala Capstone ([Coursera](https://www.coursera.org/learn/scala-capstone) only),
- * Programming Reactive Systems ([edX](https://www.edx.org/course/programming-reactive-systems) only).
+    * [Functional Programming Principles in Scala](https://www.coursera.org/learn/progfun1),
+    * [Functional Program Design in Scala](https://www.coursera.org/learn/progfun2),
+    * [Parallel programming](https://www.coursera.org/learn/parprog1),
+    * [Big Data Analysis with Scala and Spark](https://www.coursera.org/learn/scala-spark-big-data),
+    * [Functional Programming in Scala Capstone](https://www.coursera.org/learn/scala-capstone),
+ * [Programming Reactive Systems](https://www.edx.org/course/programming-reactive-systems).
 
 Note : On Coursera and edX, there is a paid version available. The only difference with the free version is that
 the paid version delivers a certificate of completion. Learn more about