MDL-40436 block_course_list: Fix bad context resolution

We were trying to get the course context of a remote course
from a completely unrelated ID. It would sometimes work if the
ID was matching the one of a local course. In other places
we are not trying to find a context for the remote course, we
simply use the $PAGE context in format_string. So the usage
of the context has been removed here too.

blocks/course_list/block_course_list.php

@@ -128,8 +128,7 @@ function get_remote_courses() {
             $this->content->items[] = get_string('remotecourses','mnet');
             $this->content->icons[] = '';
             foreach ($courses as $course) {
-                $coursecontext = context_course::instance($course->id);
-                $this->content->items[]="<a title=\"" . format_string($course->shortname, true, array('context' => $coursecontext)) . "\" ".
+                $this->content->items[]="<a title=\"" . format_string($course->shortname, true) . "\" ".
                     "href=\"{$CFG->wwwroot}/auth/mnet/jump.php?hostid={$course->hostid}&amp;wantsurl=/course/view.php?id={$course->remoteid}\">"
                     .$icon. format_string(get_course_display_name_for_list($course)) . "</a>";
             }