HPCC-8053 - Timeouts can cause superfile update inconsistencies

Locking timeouts in transactions can cause add/remove super file
inconsistencies, resulting in corrupt superfiles (wrong # of files
in meta info and/or subfiles with duplicate @num's)

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #4613 from jakesmith/hpcc-8053b

HPCC-8053 - Timeouts can cause superfile update inconsistencies

Reviewed-By: Gavin Halliday <gavin.halliday@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>