CI: tweak scan-build configuration

Clang right now does not support cleanup attribute which is causing
false positives, so the check is now disabled.
https://bugs.llvm.org/show_bug.cgi?id=3888

At the same time I've enabled all other checkers to see what happens. We
need to go though them and disable them one-by-one if necessary.
14 jobs for cleanup-errors in 6 minutes and 57 seconds (queued for 13 seconds)
Status Job ID Name Coverage
  Build
passed #99193
docker linux amd64
build:clang:linux:amd64

00:00:30

passed #99192
docker linux amd64
build:linux:amd64

00:00:30

 
  Test
passed #99199
docker linux amd64
deckard:linux:amd64

00:06:12

passed #99198
docker linux amd64
installcheck:linux:amd64

00:00:38

passed #99200
docker linux amd64
installcheck:valgrind:linux:amd64

00:00:48

passed #99195
docker
lint:c

00:01:49

failed #99196
docker allowed to fail
lint:clang-scan-build

00:00:56

passed #99194
docker
lint:lua

00:00:34

passed #99203
docker linux amd64
respdiff:iter:tcp:linux:amd64

00:02:51

passed #99204
docker linux amd64
respdiff:iter:tls:linux:amd64

00:02:36

passed #99202
docker linux amd64
respdiff:iter:udp:linux:amd64

00:02:19

passed #99197
docker linux amd64
test:linux:amd64

00:00:53

passed #99201
docker linux amd64
test:linux:amd64:valgrind

00:00:44

 
  Coverage
passed #99205
docker linux amd64
coverage

00:00:13

64.8%
 
Name Stage Failure
failed
lint:clang-scan-build Test There is an unknown failure, please try again
                                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
4 warnings generated.
CCLD daemon/kresd
scan-build: 27 bugs found.
scan-build: Run 'scan-view /builds/knot/knot-resolver/scan-results/2018-01-18-112216-14-1' to examine bug reports.
Uploading artifacts...
scan-results: found 32 matching files
Uploading artifacts to coordinator... ok
id=99196 responseStatus=201 Created token=gFb3YcAr
ERROR: Job failed: exit code 1