Update HAProxy default timeout values

The default HAProxy values are set in the layer-openstack template for
haproxy. Bring the layer-openstack-api default configuration in line
with the classic charms which do not set values in the config.yaml but
rely on the template. If any future changes are required, a change in
one place (layer-openstack) will affect all charms.

Change-Id: I045d66bf606ef57b066b4d6af1d4829eeed3bc93

config.yaml

@@ -74,28 +74,28 @@ options:
       option is set.
   haproxy-server-timeout:
     type: int
-    default: 30000
+    default:
     description: |
        Server timeout configuration in ms for haproxy, used in HA
-       configurations.
+       configurations. If not provided, default value of 90000ms is used.
   haproxy-client-timeout:
     type: int
-    default: 30000
+    default:
     description: |
        Client timeout configuration in ms for haproxy, used in HA
-       configurations.
+       configurations. If not provided, default value of 90000ms is used.
   haproxy-queue-timeout:
     type: int
-    default: 5000
+    default:
     description: |
        Queue timeout configuration in ms for haproxy, used in HA
-       configurations.
+       configurations. If not provided, default value of 9000ms is used.
   haproxy-connect-timeout:
     type: int
-    default: 5000
+    default:
     description: |
        Connect timeout configuration in ms for haproxy, used in HA
-       configurations.
+       configurations. If not provided, default value of 9000ms is used.
   dns-ha:
     type: boolean
     default: False