gc: reformat source code to conform to Linux codestyle

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

00:00:54

passed build #279330
docker linux amd64

00:01:02

passed build-asan #279331
docker linux amd64

00:01:02

passed kres-gen #279332
docker

00:00:59

 
  Test
passed build:darwin #279333
docker delayed

00:00:54

passed deckard #279334
docker linux amd64

00:02:43

passed doc #279335
docker delayed

00:01:13

passed docker #279336
dind

00:01:56

passed lint:other #279337
docker delayed

00:00:54

passed lint:pedantic #279338
docker linux amd64 delayed

00:01:14

passed lint:scan-build #279339
docker linux amd64

00:02:29

passed lint:tidy #279340
docker linux amd64

00:03:12

passed pkg:epel-7 #279341
privileged

00:01:52

passed pkg:fedora-29 #279342
privileged

00:02:30

passed respdiff:basic #279343
docker linux amd64

00:05:09

passed test:valgrind #279344
docker linux amd64 delayed

00:02:17

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

00:07:09

canceled fwd-udp6-kresd.udp6 #279347
respdiff

00:07:09

canceled fwd-udp6-unbound.tcp6 #279351
respdiff

00:07:09

canceled fwd-udp6-unbound.tls6 #279352
respdiff

00:07:09

canceled fwd-udp6-unbound.udp6 #279350
respdiff

00:07:09

canceled iter.tls6 #279349
respdiff

00:07:09

canceled iter.udp6 #279348
respdiff

00:07:09

passed pytests #279345
docker linux amd64

00:04:35

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

00:07:09

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

00:07:08

canceled resperf:iter.udp-asan #279355
respdiff

00:07:08