conf: split network host structs to util/

conf: split network host structs to util/

Continuing the refactoring of host-side storage descriptions out
of conf/domain_conf and into util/virstoragefile, this patch
focuses on details about a host name/port/transport as used by
a network storage volume.

* src/conf/domain_conf.h (virDomainDiskProtocolTransport)
(virDomainDiskHostDef, virDomainDiskHostDefClear)
(virDomainDiskHostDefFree, virDomainDiskHostDefCopy): Move...
* src/util/virstoragefile.h (virStorageNetHostTransport)
(virStorageNetHostDef, virStorageNetHostDefClear)
(virStorageNetHostDefFree, virStorageNetHostDefCopy): ...here,
with better names.
* src/util/virstoragefile.c (virStorageNetHostDefClear)
(virStorageNetHostDefFree, virStorageNetHostDefCopy): Moved from...
* src/conf/domain_conf.c (virDomainDiskHostDefClear)
(virDomainDiskHostDefFree, virDomainDiskHostDefCopy): ...here.
(virDomainDiskSourceDefClear, virDomainDiskSourceDefParse)
(virDomainDiskSourceDefFormatInternal): Adjust callers.
* src/conf/snapshot_conf.h (_virDomainSnapshotDiskDef): Likewise.
* src/conf/snapshot_conf.c (virDomainSnapshotDiskDefClear):
Likewise.
* src/qemu/qemu_command.c (qemuAddRBDHost)
(qemuParseDriveURIString, qemuParseNBDString)
(qemuBuildNetworkDriveURI, qemuParseCommandLineDisk)
(qemuParseCommandLine, qemuGetDriveSourceString): Likewise.
* src/qemu/qemu_command.h: Likewise.
* src/qemu/qemu_conf.c (qemuAddISCSIPoolSourceHost)
(qemuTranslateDiskSourcePool): Likewise.
* src/qemu/qemu_driver.c
(qemuDomainSnapshotCreateSingleDiskActive)
(qemuDomainSnapshotUndoSingleDiskActive): Likewise.
* src/storage/storage_backend_gluster.c
(virStorageFileBackendGlusterInit): Likewise.
* src/storage/storage_driver.c (virStorageFileFree)
(virStorageFileInitInternal): Likewise.
* src/storage/storage_driver.h (_virStorageFile): Likewise.
* src/libvirt_private.syms (domain_conf.h): Move symbols...
(virstoragefile.h): ...as appropriate.

Signed-off-by: Eric Blake <eblake@redhat.com>