release exec immediately if exec has no tty
release exec immediately if exec has no tty

Only signal handler operates the exex struct, we
can release exec immediately

Signed-off-by: Gao feng <7f710758e13fe1707f3aa2e93d3a8f5444b6a90e@gmail.com>

wcwxyz/hyperstart,MarioCarrilloA/hyperstart,gnawux/hyperstart,hyperhq/hyperstart,gao-feng/hyperstart,gnawux/hyperstart,MarioCarrilloA/hyperstart,laijs/hyperstart,gnawux/hyperstart,hyperhq/hyperstart,gao-feng/hyperstart,MarioCarrilloA/hyperstart,bergwolf/hyperstart,wcwxyz/hyperstart,laijs/hyperstart,bergwolf/hyperstart