Remove the old and unused log-schema.sql file

MANIFEST.in

@@ -2,7 +2,6 @@ include Makefile
 include conftest.py
 include requirements*.txt
 include version.txt
-recursive-include swh/core/sql *.sql
 recursive-include swh py.typed
 recursive-include swh/core/tests/data/ *
 recursive-include swh/core/tests/fixture/data/ *

swh/core/sql/log-schema.sql

----
---- logging data model
----
-
-create table dbversion
-(
-  version     int primary key,
-  release     timestamptz,
-  description text
-);
-
-insert into dbversion(version, release, description)
-      values(1, now(), 'Work In Progress');
-
-
-create type log_level as enum ('debug', 'info', 'warning', 'error', 'critical');
-
-create table log
-(
-  id          bigserial primary key,
-  ts          timestamptz not null default now(),
-  level       log_level not null default 'info',  -- importance
-  message     text not null,  -- human readable message
-  data        jsonb, -- extra data; when NOT NULL, must contain a key "type"
-                     -- denoting the kind of message within src_module
-  src_module  text,  -- fully-qualified source module, e.g., "swh.loader.git"
-  src_host    text,  -- FQDN source hostname, e.g., "worker03.softwareheritage.org"
-  src_pid     int    -- originating PID, relative to src_host
-);
-
-create index on log (ts);
-create index on log (src_module);
-create index on log (src_host);