HPCC-11469 Add gcc -Wparentheses

And remove some harmless warnings, mostly to remove potential
confusion over nested if else's.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #5912 from jakesmith/hpcc-11469

HPCC-11469 Add gcc -Wparentheses

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>