vmware: Fix some initialization problems

Don't leak guest if adding it to virCapabilities fails.  Also return
NULL and not pointer to free'd object with zero references in such
case.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

src/vmware/vmware_conf.c

@@ -105,14 +105,15 @@ vmwareCapsInit(void)
                                           VIR_DOMAIN_VIRT_VMWARE,
                                           NULL, NULL, 0, NULL) == NULL)
             goto error;
+        guest = NULL;
     }
 
- cleanup:
     return caps;
 
  error:
+    virCapabilitiesFreeGuest(guest);
     virObjectUnref(caps);
-    goto cleanup;
+    return NULL;
 }
 
 int