Nest: Allow modification of channels inherited from templates

Multiple definitions of same channels are forbidden, but inherited
channel can be redefined. In such case channel options are merged.
32 jobs for int-new in 6 minutes and 55 seconds (queued for 8 seconds)
Status Job ID Name Coverage
  Image
passed #96494
dind
docker_centos-6-amd64

00:00:26

passed #96495
dind
docker_centos-7-amd64

00:00:26

passed #96484
dind
docker_debian-7-amd64

00:00:36

passed #96488
dind
docker_debian-7-i386

00:00:41

passed #96485
dind
docker_debian-8-amd64

00:00:40

passed #96489
dind
docker_debian-8-i386

00:00:30

passed #96486
dind
docker_debian-9-amd64

00:00:38

passed #96490
dind
docker_debian-9-i386

00:00:30

passed #96487
dind
docker_debian-testing-amd64

00:00:41

passed #96491
dind
docker_debian-testing-i386

00:00:31

passed #96492
dind
docker_fedora-25-amd64

00:00:31

passed #96493
dind
docker_fedora-26-amd64

00:00:32

passed #96496
dind
docker_opensuse-42_3-amd64

00:00:58

passed #96497
dind
docker_ubuntu-14_04-amd64

00:00:57

passed #96498
dind
docker_ubuntu-16_04-amd64

00:00:57

 
  Build
passed #96505
docker linux amd64
build-centos-6-amd64

00:00:38

passed #96506
docker linux amd64
build-centos-7-amd64

00:01:21

passed #96499
docker linux amd64
build-debian-7-amd64

00:00:40

passed #96510
docker linux amd64
build-debian-7-i386

00:01:27

passed #96500
docker linux amd64
build-debian-8-amd64

00:01:29

passed #96511
docker linux amd64
build-debian-8-i386

00:00:46

passed #96501
docker linux amd64
build-debian-9-amd64

00:00:45

passed #96512
docker linux amd64
build-debian-9-i386

00:01:52

passed #96502
docker linux amd64
build-debian-testing-amd64

00:01:37

passed #96513
docker linux amd64
build-debian-testing-i386

00:00:47

passed #96503
docker linux amd64
build-fedora-25-amd64

00:00:42

passed #96504
docker linux amd64
build-fedora-26-amd64

00:01:27

passed #96514
freebsd amd64
build-freebsd-11-amd64

00:04:22

passed #96515
freebsd i386
build-freebsd-11-i386

00:04:27

passed #96507
docker linux amd64
build-opensuse-42_3-amd64

00:00:40

passed #96508
docker linux amd64
build-ubuntu-14_04-amd64

00:01:26

passed #96509
docker linux amd64
build-ubuntu-16_04-amd64

00:00:42