libvirt: introduce domainCreateWithFlags API

libvirt: introduce domainCreateWithFlags API

Persistent domain creation needs the same features as transient
domains, but virDomainCreate lacks the flags argument present in
virDomainCreateXML.  virDomainCreateFlags is already claimed as
a public enum, so we have to break convention and expose
virDomainCreateWithFlags.

* include/libvirt/libvirt.h.in (virDomainCreateWithFlags): Add.
* src/driver.h (virDrvDomainCreateWithFlags): Internal API.
* src/libvirt.c (virDomainCreateWithFlags): Glue public API to
driver API.
* src/libvirt_public.syms (LIBVIRT_0.8.2): Expose public API.
* src/esx/esx_driver.c (esxDriver): Add stub for driver.
* src/lxc/lxc_driver.c (lxcDriver): Likewise.
* src/opennebula/one_driver.c (oneDriver): Likewise.
* src/openvz/openvz_driver.c (openvzDriver): Likewise.
* src/phyp/phyp_driver.c (phypDriver): Likewise.
* src/qemu/qemu_driver.c (qemuDriver): Likewise.
* src/remote/remote_driver.c (remote_driver): Likewise.
* src/test/test_driver.c (testDriver): Likewise.
* src/uml/uml_driver.c (umlDriver): Likewise.
* src/vbox/vbox_tmpl.c (Driver): Likewise.
* src/xen/xen_driver.c (xenUnifiedDriver): Likewise.
* src/xenapi/xenapi_driver.c (xenapiDriver): Likewise.