Increase configure_swap_size to 8192

https://review.opendev.org/#/c/750941/ changes
use dd and limit swap size to 1024MB in
openstack-zuul-jobs configure_swap role, caused
the OOM issue during container image prepare step.

Earlier the swap size was 8192, in order to fix that,
the configure-swap role variable configure_swap_size
is setted to 8192 at playbook level and remove the vars
defined at job level in https://review.opendev.org/751828

Change-Id: I80c1ee16662fa4e50e46f864d0e70847731449df
Related-Bug: #1895290
Related-Bug: #1895288
Signed-off-by: Bhagyashri Shewale <bshewale@redhat.com>
Co-authored-by: Chandan Kumar (raukadah) <chkumar@redhat.com>

roles/prepare-node/tasks/main.yaml

@@ -1,4 +1,6 @@
 - name: Swap is essential as we are not meeting memory requirements
+  vars:
+    configure_swap_size: 8192
   include_role:
     name: configure-swap
 

zuul.d/base.yaml

@@ -181,7 +181,6 @@
       environment_infra: osinfra
       environment_type: multinode
       common_featureset: featureset-multinode-common.yml
-      configure_swap_size: 4096
       playbooks:
         - quickstart.yml
         - multinode-undercloud.yml