try to prevent stackhpc env image build connection drops

Author: sjpb

environments/.stackhpc/ansible.cfg

@@ -12,5 +12,5 @@ roles_path = ../../ansible/roles
 filter_plugins = ../../ansible/filter_plugins
 
 [ssh_connection]
-ssh_args = -o ControlMaster=auto -o ControlPath=~/.ssh/%r@%h-%p -o ControlPersist=240s -o PreferredAuthentications=publickey -o UserKnownHostsFile=/dev/null
+ssh_args = -ol ServerAliveInterval=10 -o ControlMaster=auto -o ControlPath=~/.ssh/%r@%h-%p -o ControlPersist=240s -o PreferredAuthentications=publickey -o UserKnownHostsFile=/dev/null
 pipelining = True