Remove obsolete get_backup_driver functions

With [1], backup driver modules are no longer expected to provide a
get_backup_driver function. This patch removes them all, as the
backup manager no longer calls them.

[1] https://review.opendev.org/595372

Change-Id: Ic2562b98c00cbf567503edf275b6d7d97820058c

cinder/backup/drivers/ceph.py

@@ -1290,7 +1290,3 @@ class CephBackupDriver(driver.BackupDriver):
             LOG.debug("Delete of backup '%(backup)s' for volume "
                       "'%(volume)s' finished.",
                       {'backup': backup.id, 'volume': backup.volume_id})
-
-
-def get_backup_driver(context):
-    return CephBackupDriver(context)

cinder/backup/drivers/gcs.py

@@ -394,7 +394,3 @@ class GoogleMediaIoBaseDownload(http.MediaIoBaseDownload):
 
         else:
             raise http.HttpError(resp, content, uri=self._uri)
-
-
-def get_backup_driver(context):
-    return GoogleBackupDriver(context)

cinder/backup/drivers/glusterfs.py

@@ -93,7 +93,3 @@ class GlusterfsBackupDriver(posix.PosixBackupDriver):
                           run_as_root=True)
 
         return mount_path
-
-
-def get_backup_driver(context):
-    return GlusterfsBackupDriver(context)

cinder/backup/drivers/nfs.py

@@ -103,7 +103,3 @@ class NFSBackupDriver(posix.PosixBackupDriver):
                           run_as_root=True)
 
         return mount_path
-
-
-def get_backup_driver(context):
-    return NFSBackupDriver(context)

cinder/backup/drivers/posix.py

@@ -148,7 +148,3 @@ class PosixBackupDriver(chunkeddriver.ChunkedBackupDriver):
 
     def get_extra_metadata(self, backup, volume):
         return None
-
-
-def get_backup_driver(context):
-    return PosixBackupDriver(context)

cinder/backup/drivers/swift.py

@@ -392,13 +392,3 @@ class SwiftBackupDriver(chunkeddriver.ChunkedBackupDriver):
             LOG.exception("Can not get Swift capabilities during backup "
                           "driver initialization.")
             raise
-
-
-def get_backup_driver(context):
-    # NOTE(mdovgal): at the moment of backup service start we need to
-    #                get driver class instance and for swift at that moment
-    #                we can't get all necessary information like endpoints
-    #                from context, so we have exception as a result.
-    if context.user is None:
-        return SwiftBackupDriver(None)
-    return SwiftBackupDriver(context)

cinder/backup/drivers/tsm.py

@@ -541,7 +541,3 @@ class TSMBackupDriver(driver.BackupDriver):
                        'err': err})
 
         LOG.debug('Delete %s finished.', backup['id'])
-
-
-def get_backup_driver(context):
-    return TSMBackupDriver(context)

cinder/tests/unit/backup/fake_service.py

@@ -32,7 +32,3 @@ class FakeBackupService(driver.BackupDriver):
         # otherwise we return without error
         if backup['display_name'] == 'fail_on_delete':
             raise IOError('fake')
-
-
-def get_backup_driver(context):
-    return FakeBackupService(context)

cinder/tests/unit/backup/fake_service_with_verify.py

@@ -21,7 +21,3 @@ class FakeBackupServiceWithVerify(driver.BackupDriverWithVerify,
                                   fake_service.FakeBackupService):
     def verify(self, backup):
         pass
-
-
-def get_backup_driver(context):
-    return FakeBackupServiceWithVerify(context)