vmware: Avoid NULL dereference for 'caps'

When virCapabilitiesNew() fails, caps will be NULL resulting in possible
core when deref'd in cpuDataFree() call.

src/vmware/vmware_conf.c

@@ -127,7 +127,8 @@ vmwareCapsInit(void)
 
 cleanup:
     virCPUDefFree(cpu);
-    cpuDataFree(caps->host.arch, data);
+    if (caps)
+        cpuDataFree(caps->host.arch, data);
 
     return caps;