Merge pull request kubevirt#2793 from kubevirt-bot/cherry-pick-2791-t…

…o-release-0.13

[release-0.13] Fix nil exception when agent polling can't reach libvirt

pkg/virt-launcher/virtwrap/cli/libvirt.go

@@ -182,7 +182,13 @@ func (l *LibvirtConnection) ListAllDomains(flags libvirt.ConnectListAllDomainsFl
 // command - the qemu command, for example this gets the interfaces: {"execute":"guest-network-get-interfaces"}
 // domainName -  the qemu domain name
 func (l *LibvirtConnection) QemuAgentCommand(command string, domainName string) (string, error) {
+	if err := l.reconnectIfNecessary(); err != nil {
+		return "", err
+	}
 	domain, err := l.Connect.LookupDomainByName(domainName)
+	if err != nil {
+		return "", err
+	}
 	result, err := domain.QemuAgentCommand(command, libvirt.DOMAIN_QEMU_AGENT_COMMAND_DEFAULT, uint32(0))
 	return result, err
 }