gc: reformat source code to conform to Linux codestyle

Main motivation is getting rid of tab-space mix.
27 jobs for <span class="ref-name">kr_cache_gc</span> in 13 minutes and 27 seconds (queued for 10 seconds)
Status Job ID Name Coverage
  Build
passed #279329
docker linux amd64
archive

00:00:54

passed #279330
docker linux amd64
build

00:01:02

passed #279331
docker linux amd64
build-asan

00:01:02

passed #279332
docker
kres-gen

00:00:59

 
  Test
passed #279333
docker delayed
build:darwin

00:00:54

passed #279334
docker linux amd64
deckard

00:02:43

passed #279335
docker delayed
doc

00:01:13

passed #279336
dind
docker

00:01:56

passed #279337
docker delayed
lint:other

00:00:54

passed #279338
docker linux amd64 delayed
lint:pedantic

00:01:14

passed #279339
docker linux amd64
lint:scan-build

00:02:29

passed #279340
docker linux amd64
lint:tidy

00:03:12

passed #279341
privileged
pkg:epel-7

00:01:52

passed #279342
privileged
pkg:fedora-29

00:02:30

passed #279343
docker linux amd64
respdiff:basic

00:05:09

passed #279344
docker linux amd64 delayed
test:valgrind

00:02:17

 
  Extended
canceled #279346
respdiff
fwd-tls6-kresd.udp6

00:07:09

canceled #279347
respdiff
fwd-udp6-kresd.udp6

00:07:09

canceled #279351
respdiff
fwd-udp6-unbound.tcp6

00:07:09

canceled #279352
respdiff
fwd-udp6-unbound.tls6

00:07:09

canceled #279350
respdiff
fwd-udp6-unbound.udp6

00:07:09

canceled #279349
respdiff
iter.tls6

00:07:09

canceled #279348
respdiff
iter.udp6

00:07:09

passed #279345
docker linux amd64
pytests

00:04:35

canceled #279353
respdiff
resperf:fwd-tls6.udp-asan

00:07:09

canceled #279354
respdiff
resperf:fwd-udp6.udp-asan

00:07:08

canceled #279355
respdiff
resperf:iter.udp-asan

00:07:08