npe guard for get host info on vmware (#11054)

Co-authored-by: Daan Hoogland <dahn@apache.org>

Author: DaanHoogland

vmware-base/src/main/java/com/cloud/hypervisor/vmware/mo/HostMO.java

@@ -75,7 +75,7 @@
 
 public class HostMO extends BaseMO implements VmwareHypervisorHost {
     private static final Logger s_logger = Logger.getLogger(HostMO.class);
-    Map<String, VirtualMachineMO> _vmCache = new HashMap<String, VirtualMachineMO>();
+    Map<String, VirtualMachineMO> _vmCache = new HashMap<>();
 
     //Map<String, String> _vmInternalNameMapCache = new HashMap<String, String>();
 
@@ -320,6 +320,11 @@ public AboutInfo getHostAboutInfo() throws Exception {
 
     public VmwareHostType getHostType() throws Exception {
         AboutInfo aboutInfo = getHostAboutInfo();
+        if (aboutInfo == null) {
+            String msg = "no type info about host known, assuming ESXi";
+            s_logger.warn(msg);
+            return VmwareHostType.ESXi;
+        }
         if ("VMware ESXi".equals(aboutInfo.getName()))
             return VmwareHostType.ESXi;
         else if ("VMware ESX".equals(aboutInfo.getName()))