Now that the public APIs always use unsigned flags, the internal
driver callbacks might as well do likewise.

* src/driver.h (vrDrvOpen, virDrvDomainCoreDump)
(virDrvDomainGetXMLDesc, virDrvNetworkGetXMLDesc)
(virDrvNWFilterGetXMLDesc): Update type.
* src/remote/remote_protocol.x (remote_open_args)
(remote_domain_core_dump_args, remote_domain_get_xml_desc_args)
(remote_network_get_xml_desc_args)
(remote_nwfilter_get_xml_desc_args): Likewise.
* src/test/test_driver.c: Update clients.
* src/remote/remote_driver.c: Likewise.
* src/xen/xen_hypervisor.c: Likewise.
* src/xen/xen_hypervisor.h: Likewise.
* src/xen/xen_driver.c: Likewise.
* src/xen/xend_internal.c: Likewise.
* src/xen/xend_internal.h: Likewise.
* src/xen/xm_internal.c: Likewise.
* src/xen/xm_internal.h: Likewise.
* src/xen/xs_internal.c: Likewise.
* src/xen/xs_internal.h: Likewise.
* src/xen/xen_inotify.c: Likewise.
* src/xen/xen_inotify.h: Likewise.
* src/phyp/phyp_driver.c: Likewise.
* src/openvz/openvz_driver.c: Likewise.
* src/vmware/vmware_driver.c: Likewise.
* src/vbox/vbox_driver.c: Likewise.
* src/vbox/vbox_tmpl.c: Likewise.
* src/xenapi/xenapi_driver.c: Likewise.
* src/esx/esx_driver.c: Likewise.
* src/esx/esx_interface_driver.c: Likewise.
* src/esx/esx_network_driver.c: Likewise.
* src/esx/esx_storage_driver.c: Likewise.
* src/esx/esx_device_monitor.c: Likewise.
* src/esx/esx_secret_driver.c: Likewise.
* src/esx/esx_nwfilter_driver.c: Likewise.
* src/interface/netcf_driver.c: Likewise.
* src/nwfilter/nwfilter_driver.c: Likewise.
* src/libxl/libxl_driver.c: Likewise.
* src/qemu/qemu_driver.c: Likewise.
* src/lxc/lxc_driver.c: Likewise.
* src/uml/uml_driver.c: Likewise.
* src/network/bridge_driver.c: Likewise.
* src/secret/secret_driver.c: Likewise.
* src/storage/storage_driver.c: Likewise.
* src/node_device/node_device_hal.c: Likewise.
* src/node_device/node_device_udev.c: Likewise.
* src/remote_protocol-structs: Likewise.