ldb: Free memory when repacking database

The msg for each database record is allocated on the module context, but
never freed. The module seems like it could be a long-running context (as
the database would normally get repacked by the samba executable).

Even if it's not a proper leak, it shouldn't hurt to cleanup the memory.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14059

Signed-off-by: Tim Beale <[email protected]>
Reviewed-by: Andrew Bartlett <[email protected]>
Reviewed-by: Garming Sam <[email protected]>

Autobuild-User(master): Garming Sam <[email protected]>
Autobuild-Date(master): Tue Aug 20 04:57:10 UTC 2019 on sn-devel-184

lib/ldb/ldb_key_value/ldb_kv_index.c

@@ -3599,6 +3599,7 @@ static int re_pack(struct ldb_kv_private *ldb_kv,
 			  ctx->count);
 	}
 
+	talloc_free(msg);
 	return 0;
 }