remove os_family variable from bootstrap-os (#3962)

* remove os_family variable from bootstrap-os

* quote the conditions another time to fix the syntax error

roles/bootstrap-os/defaults/main.yml

 ---
-bootstrap_os:
-os_family: "{{bootstrap_os}}"
-
 pip_python_coreos_modules:
   - httplib2
   - six

roles/bootstrap-os/tasks/main.yml

@@ -5,45 +5,26 @@
   changed_when: false
   environment: {}
 
-- name: Set bootstrap_os
-  set_fact:
-    os_family: >-
-      {%- if 'Ubuntu' in os_release.stdout -%}
-      ubuntu
-      {%- elif 'Debian' in os_release.stdout -%}
-      debian
-      {%- elif 'CoreOS' in os_release.stdout -%}
-      coreos
-      {%- elif 'Fedora' in os_release.stdout -%}
-      fedora
-      {%- elif 'CentOS' in os_release.stdout -%}
-      centos
-      {%- elif 'OpenSUSE' in os_release.stdout -%}
-      opensuse
-      {%- elif 'Clear Linux OS' in os_release.stdout -%}
-      clearlinux
-      {%- endif -%}
-
 - include_tasks: bootstrap-ubuntu.yml
-  when: os_family == "ubuntu"
+  when: '"Ubuntu" in os_release.stdout'
 
 - include_tasks: bootstrap-debian.yml
-  when: os_family == "debian"
+  when: '"Debian" in os_release.stdout'
 
 - include_tasks: bootstrap-coreos.yml
-  when: os_family == "coreos"
+  when: '"CoreOS" in os_release.stdout'
 
 - include_tasks: bootstrap-fedora.yml
-  when: os_family == "fedora"
+  when: '"Fedora" in os_release.stdout'
 
 - include_tasks: bootstrap-centos.yml
-  when: os_family == "centos"
+  when: '"CentOS" in os_release.stdout'
 
 - include_tasks: bootstrap-opensuse.yml
-  when: os_family == "opensuse"
+  when: '"OpenSUSE" in os_release.stdout'
 
 - include_tasks: bootstrap-clearlinux.yml
-  when: os_family == "clearlinux"
+  when: '"Clear Linux OS" in os_release.stdout'
 
 - import_tasks: setup-pipelining.yml