svn.loader: Let core loader update snapshot & visit at the same time

Prior to this commit, the loader svn did an origin visit update to set the
snapshot. And then the loader core did the update to set the status.

This removes the origin visit update on the snapshot to let the loader core do
everything.

requirements-swh.txt

 swh.storage >= 0.0.178
 swh.model >= 0.0.60
 swh.scheduler >= 0.0.39
-swh.loader.core >= 0.0.81
+swh.loader.core >= 0.0.85

swh/loader/svn/loader.py

@@ -15,11 +15,11 @@ import tempfile
 
 from mmap import mmap, ACCESS_WRITE
 from subprocess import Popen
-from typing import Iterator, List, Tuple
+from typing import Iterator, List, Optional, Tuple
 
 from swh.model import hashutil
 from swh.model.model import (
-    Content, Directory, Origin, SkippedContent, Revision, Snapshot,
+    Content, Directory, Origin, SkippedContent, Revision, Sha1Git, Snapshot,
     SnapshotBranch, TargetType
 )
 from swh.model import from_disk
@@ -105,6 +105,7 @@ class SvnLoader(BaseLoader):
         self.start_from_scratch = start_from_scratch
         self.swh_revision = swh_revision
         self.max_content_length = self.config['max_content_size']
+        self.snapshot = None
 
     def pre_cleanup(self):
         """Cleanup potential dangling files from prior runs (e.g. OOM killed
@@ -514,6 +515,9 @@ Local repository not cleaned up for investigation: %s''' % (
             self._revisions.append(rev)
         return True  # next svn revision
 
+    def get_snapshot_id(self) -> Optional[Sha1Git]:
+        return self.snapshot.id if self.snapshot else None
+
     def store_data(self):
         """We store the data accumulated in internal instance variable.  If
            the iteration over the svn revisions is done, we create the
@@ -528,14 +532,11 @@ Local repository not cleaned up for investigation: %s''' % (
         self.storage.revision_add(self._revisions)
 
         if self.done:  # finish line, snapshot!
-            snapshot = self.generate_and_load_snapshot(
+            self.snapshot = self.generate_and_load_snapshot(
                 revision=self._last_revision,
                 snapshot=self._snapshot
             )
             self.flush()
-            if snapshot:
-                self.storage.origin_visit_update(
-                    self.origin.url, self.visit.visit, snapshot=snapshot.id)
 
         # reset internal state for next iteration
         self._revisions = []