fixed wrong var name

tasks/main.yml

@@ -7,7 +7,7 @@
 
 - name: '[INSTALL] - Add repository for nodejs'
   apt_repository:
-    repo: deb https://deb.nodesource.com/node_{{ etherpad_nodejs_version }}.x nodistro main
+    repo: deb https://deb.nodesource.com/node_{{ nodejs_version }}.x nodistro main
     state: present
     update_cache: yes
     filename: 'nodesource'
@@ -16,4 +16,4 @@
   apt:
     name: "{{ nodejs_apt }}"
     update_cache: yes
-    state: latest
+    state: latest