Fix _do_log conditions in log_exec_* macros

Fix _do_log conditions in log_exec_* macros

The expression for calculation of the _do_log values in the log_exec_*
macros need to be the same as the unit_log_level_test() function, used
to calculate _do_log in unit.h. The only difference between execute.h
and unit.h is the lack of the Unit structure.

Fixes: b646fc324a ("core: ensure execute/spawn functions can work without Unit object")
Fixes: 210ca71cb5 ("core/execute: clean up log_exec_full_errno and friends")
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>