* src/xen/xm_internal.c (xenXMConfigGetULong): Remove useless and
misleading test (always false) for val->str == NULL before code that
always dereferences val->str.  "val" comes from virConfGetValue, and
at that point, val->str is guaranteed to be non-NULL.
(xenXMConfigGetBool): Likewise.
* src/util/conf.c (virConfSetValue): Ensure that vir->str is never NULL,
not even if someone tries to set such a value via virConfSetValue.