Don't use FQDN in CN for libvirt certs

According to RFC CN is limited to 63 characters, this patch
updates common_name for libvirt certs to use hostname only.
FQDN is added to alvernative names.

Change-Id: Ib509d73faeb17bcc423a2590de730baddd209d81
Related-Prod: PROD-28275
(cherry picked from commit c464b3b13162adab0512df7c366c0d3643d451ac)
diff --git a/salt/minion/cert/libvirtd/vnc_server.yml b/salt/minion/cert/libvirtd/vnc_server.yml
index ae35ff2..2929869 100644
--- a/salt/minion/cert/libvirtd/vnc_server.yml
+++ b/salt/minion/cert/libvirtd/vnc_server.yml
@@ -10,7 +10,10 @@
         qemu_vnc_server:
           host: ${_param:salt_minion_ca_host}
           authority: ${_param:qemu_vnc_ca_authority}
-          common_name: ${linux:system:name}.${_param:cluster_domain}
+          # NOTE(vsaienko) according to RFC2380 CN is limited to 63 chars
+          # Set CN without domain name to fit this requirement.
+          # FQDN is included into alternative names field.
+          common_name: ${linux:system:name}
           signing_policy: cert_server
           alternative_names: >
             IP:${_param:cluster_local_address},