Make sure to delete all the realisation refs

Deleting just one will only work in the test cases where I didn’t bother
creating too many of them :p

src/libstore/ca-specific-schema.sql

@@ -21,7 +21,7 @@ create index if not exists IndexRealisations on Realisations(drvPath, outputName
 -- realisations
 create trigger if not exists DeleteSelfRefsViaRealisations before delete on ValidPaths
   begin
-    delete from RealisationsRefs where realisationReference = (
+    delete from RealisationsRefs where realisationReference in (
       select id from Realisations where outputPath = old.id
     );
   end;

src/libstore/local-store.cc

@@ -148,7 +148,7 @@ void migrateCASchema(SQLite& db, Path schemaPath, AutoCloseFD& lockFd)
             db.exec(R"(
                 create trigger if not exists DeleteSelfRefsViaRealisations before delete on ValidPaths
                 begin
-                    delete from RealisationsRefs where realisationReference = (
+                    delete from RealisationsRefs where realisationReference in (
                     select id from Realisations where outputPath = old.id
                     );
                 end;