`cert_client` minion `signing_policy` list for VNC CA cert is un-hardcoded

  * It needed because a service engineer is able to set arbitrary hostname for control nodes.
    It allows to set arbitrary hostname pattern where nova_novncproxy service placement.

Change-Id: I0f7188de505d7d212a9ad0649771f955bec59d12
Related-PROD: PROD-30917
(cherry picked from commit 888c07e08a68312727d1ca62122b6cd2ae7fcefd)
diff --git a/salt/minion/ca/qemu-vnc_ca.yml b/salt/minion/ca/qemu-vnc_ca.yml
index a4583ad..d787fb2 100644
--- a/salt/minion/ca/qemu-vnc_ca.yml
+++ b/salt/minion/ca/qemu-vnc_ca.yml
@@ -6,6 +6,7 @@
     qemu_vnc_ca_organization: Mirantis
     qemu_vnc_ca_days_valid_authority: 3650
     qemu_vnc_ca_days_valid_certificate: 365
+    qemu_vnc_ca_signing_policy_cert_client_minions: 'ctl*'
   salt:
     minion:
       ca:
@@ -24,7 +25,7 @@
               minions: '*'
             cert_client:
               type: v3_edge_cert_client
-              minions: 'ctl*'
+              minions: ${_param:qemu_vnc_ca_signing_policy_cert_client_minions}
           days_valid:
             authority: ${_param:qemu_vnc_ca_days_valid_authority}
             certificate: ${_param:qemu_vnc_ca_days_valid_certificate}