Do not use "source" balance strategy for haproxy services for openstack

[vuntz]

Fixes are here:

• [backport] Rework haproxy config for stickiness and balance strategy crowbar-ha#2
• [backport] horizon: Configure stickiness with haproxy #33

We want to spread the load more evenly.
For master the fixes are:

• Rework haproxy config for stickiness and balance strategy crowbar/crowbar-ha#179
• horizon: Configure stickiness with haproxy crowbar/crowbar-openstack#841

Todo

• backport Rework haproxy config for stickiness and balance strategy crowbar/crowbar-ha#179
• backport horizon: Configure stickiness with haproxy crowbar/crowbar-openstack#841

[vuntz]

For master, I did crowbar/crowbar-ha#179 and crowbar#841

[mkoderer]

releated to sap custom wrapper (crowbar-sapcustom-soc6/blob/master/recipes/haproxy.rb#L8)

[matelakat]

Backport for crowbar/crowbar-ha#179:

• [backport] Rework haproxy config for stickiness and balance strategy crowbar-ha#2

Backport for crowbar#841:

• [backport] horizon: Configure stickiness with haproxy #33

[matelakat]

Re-triggered CI on the PRs

[vuntz]

@mkoderer: I'd drop the critical tag here, as the custom wrapper cookbook enables this. We do have pull requests for this if still considered critical (but it'd require some changes in how things are currently configured).