ansible: Change all our group names from foo-bar to foo_bar or foo-bar-baz to foo_bar_baz

In ansible 2.8 the - character isn't supposed to be valid in group names.
While we could override this, might has well just bite the bullet and change it.
So, just switch all group names to use _ instead of -

Signed-off-by: Kevin Fenzi <kevin@scrye.com>

playbooks/groups/mirrormanager.yml

@@ -1,7 +1,7 @@
 - import_playbook: "/srv/web/infra/ansible/playbooks/include/virt-create.yml myhosts=mm:mm-stg"
 
 - name: make the boxe be real for real
-  hosts: mm:mm-stg
+  hosts: mm:mm_stg
   user: root
   gather_facts: True
 
@@ -32,7 +32,7 @@
   - import_tasks: "{{ handlers_path }}/restart_services.yml"
 
 - name: Deploy the backend
-  hosts: mm-backend:mm-backend-stg
+  hosts: mm_backend:mm_backend_stg
   user: root
   gather_facts: True
 
@@ -50,7 +50,7 @@
   - import_tasks: "{{ handlers_path }}/restart_services.yml"
 
 - name: Deploy the crawler
-  hosts: mm-crawler:mm-crawler-stg
+  hosts: mm_crawler:mm_crawler_stg
   user: root
   gather_facts: True
 
@@ -69,7 +69,7 @@
   - import_tasks: "{{ handlers_path }}/restart_services.yml"
 
 - name: Deploy the frontend (web-app)
-  hosts: mm-frontend:mm-frontend-stg
+  hosts: mm_frontend:mm_frontend_stg
   user: root
   gather_facts: True
 
@@ -87,7 +87,7 @@
 # Do this one last, since the mirrormanager user needs to exist so that it can
 # own the fedmsg certs we put in place here.
 - name: Put fedmsg stuff in place
-  hosts: mm:mm-stg
+  hosts: mm:mm_stg
   user: root
   gather_facts: True