Allow to exclude roles from plays with --exclude-roles command line parameter

tasks/main.yml

 ---
 # file: roles/spideroak/tasks/main.yml
 
-- name: "Check SpiderOak Requirement"
-  shell: ls /usr/bin/SpiderOakONE
-  register: spideroak_available
-  failed_when: false
-
-- name: "Apt Key"
-  apt_key:
-    url='https://spideroak.com/dist/spideroak-apt-2013.asc'
-    state=present
-
-- name: "Apt Repository"
-  apt_repository:
-    repo='deb http://apt.spideroak.com/ubuntu-spideroak-hardy/ release restricted'
-    state='present'
-
-- name: "Install SpiderOak Agent"
-  apt:
-    pkg='spideroak'
-    state='installed'
-    update_cache=yes
-
-- include: register.yml
-  when: spideroak_available is defined and spideroak_available.stdout != '/usr/bin/SpiderOakONE'
-
-- name: "Add Directories to SpiderOak"
-  shell: SpiderOakONE --include-dir={{ item }}
-  with_items: '{{ spideroak_include }}'
+- include: spideroak.yml
+  when: '"spideroak" not in excluded_roles'

tasks/spideroak.yml

+---
+# file: roles/spideroak/tasks/spideroak.yml
+
+- name: "Check SpiderOak Requirement"
+  shell: ls /usr/bin/SpiderOakONE
+  register: spideroak_available
+  failed_when: false
+
+- name: "Apt Key"
+  apt_key:
+    url='https://spideroak.com/dist/spideroak-apt-2013.asc'
+    state=present
+
+- name: "Apt Repository"
+  apt_repository:
+    repo='deb http://apt.spideroak.com/ubuntu-spideroak-hardy/ release restricted'
+    state='present'
+
+- name: "Install SpiderOak Agent"
+  apt:
+    pkg='spideroak'
+    state='installed'
+    update_cache=yes
+
+- include: register.yml
+  when: spideroak_available is defined and spideroak_available.stdout != '/usr/bin/SpiderOakONE'
+
+- name: "Add Directories to SpiderOak"
+  shell: SpiderOakONE --include-dir={{ item }}
+  with_items: '{{ spideroak_include }}'