common/config: Introduce _exit wrapper around exit command

common/config: Introduce _exit wrapper around exit command

We should always set the value of status correctly when we are exiting.
Else, "$?" might not give us the correct value.
If we see the following trap
handler registration in the check script:

if $OPTIONS_HAVE_SECTIONS; then
     trap "_kill_seq; _summary; exit \$status" 0 1 2 3 15
else
     trap "_kill_seq; _wrapup; exit \$status" 0 1 2 3 15
fi

So, "exit 1" will exit the check script without setting the correct
return value. I ran with the following local.config file:

[xfs_4k_valid]
FSTYP=xfs
TEST_DEV=/dev/loop0
TEST_DIR=/mnt1/test
SCRATCH_DEV=/dev/loop1
SCRATCH_MNT=/mnt1/scratch

[xfs_4k_invalid]
FSTYP=xfs
TEST_DEV=/dev/loop0
TEST_DIR=/mnt1/invalid_dir
SCRATCH_DEV=/dev/loop1
SCRATCH_MNT=/mnt1/scratch

This caused the init_rc() to catch the case of invalid _test_mount
options. Although the check script correctly failed during the execution
of the "xfs_4k_invalid" section, the return value was 0, i.e "echo $?"
returned 0. This is because init_rc exits with "exit 1" without
correctly setting the value of "status". IMO, the correct behavior
should have been that "$?" should have been non-zero.

The next patch will replace exit with _exit.

Signed-off-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>