roles: Remove unreachable "packages" tags

After reörganizing for dynamic includes these tags will never be reached
because the children of dynamic includes do not inherit tags from their
parents as they did with static imports.

roles/nginx/tasks/letsencrypt.yml

@@ -17,20 +17,14 @@
   - name: Install certbot dependencies (Ubuntu 16.04)
     when: ansible_distribution == 'Ubuntu' and ansible_distribution_version is version_compare('16.04', '==')
     apt: name={{ letsencrypt_deps_ubuntu_xenial }} state=present update_cache=yes
-    tags:
-      - packages
 
   - name: Install certbot dependencies (Ubuntu 18.04)
     when: ansible_distribution == 'Ubuntu' and ansible_distribution_version is version_compare('18.04', '==')
     apt: name={{ letsencrypt_deps_ubuntu_bionic }} state=present update_cache=yes
-    tags:
-      - packages
 
   - name: Install certbot dependencies (Debian 9)
     when: ansible_distribution == 'Debian' and ansible_distribution_major_version is version_compare('9', '==')
     apt: name={{ letsencrypt_deps_debian_stretch }} state=present update_cache=yes
-    tags:
-      - packages
   tags: letsencrypt
 
 # vim: set ts=2 sw=2: