Core & Internals: remove support for old distances table format

The code was intended to allow both 1.29 and 1.30 servers to run
in parallel on the same database. This should have no effect on
everybody who correctly applied the migrations.

lib/rucio/db/sqla/models.py

@@ -1408,24 +1408,12 @@ class SourceHistory(BASE, ModelBase):
                    )
 
 
-# Compatibility code to permit 1.30 to run with a distances table from the 1.29 database schema
-# TODO: remove this code in rucio 1.31
-_distance_column_name = 'distance'
-_engine = get_engine()
-if _engine.dialect.name in ['oracle', 'mysql', 'postgresql']:
-    _insp = inspect(_engine)
-    if _engine.dialect.name in ['oracle', 'postgresql'] or BASE.metadata.schema in _insp.get_schema_names():
-        if 'distances' in _insp.get_table_names(schema=BASE.metadata.schema):
-            if any(c['name'] == 'ranking' for c in _insp.get_columns(table_name='distances', schema=BASE.metadata.schema)):
-                _distance_column_name = 'ranking'
-
-
 class Distance(BASE, ModelBase):
     """Represents distance between rses"""
     __tablename__ = 'distances'
     src_rse_id: Mapped[uuid.UUID] = mapped_column(GUID())
     dest_rse_id: Mapped[uuid.UUID] = mapped_column(GUID())
-    distance: Mapped[Optional[int]] = mapped_column(Integer(), name=_distance_column_name)
+    distance: Mapped[Optional[int]] = mapped_column(Integer())
     _table_args = (PrimaryKeyConstraint('src_rse_id', 'dest_rse_id', name='DISTANCES_PK'),
                    ForeignKeyConstraint(['src_rse_id'], ['rses.id'], name='DISTANCES_SRC_RSES_FK'),
                    ForeignKeyConstraint(['dest_rse_id'], ['rses.id'], name='DISTANCES_DEST_RSES_FK'),