HPCC-8643 Fix memory leaks in ESP EclWatch services

Valgrind shows several memory leaks (4789 bytes in 63 blocks) when
running ESP EclWatch services. This fix solves the leaks in ESP
EclWatch services.

Signed-off-by: Kevin Wang <kevin.wang@lexisnexis.com>
Merge pull request #3899 from wangkx/fix_mem_leaks

HPCC-8643 Fix memory leaks in ESP EclWatch services

Reviewed-By: Gavin Halliday <gavin.halliday@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>