Add Content-Type header in PushImageLayerRegistry

Docker-DCO-1.1-Signed-off-by: Gabor Nagy <mail@aigeruth.hu> (github: Aigeruth)
Added :neckbeard: RMS the founder of :water_buffalo: GNU and :free: as in :free:dom software

Docker-DCO-1.1-Signed-off-by: Aleksandrs Fadins <aleks@s-ko.net> (github: muchweb)
Removed :neckbeard: RMS test case

Docker-DCO-1.1-Signed-off-by: Aleksandrs Fadins <aleks@s-ko.net> (github: muchweb)
contrib/init/systemd: add philips as MAINTAINER

As requested after #7021 add me as a maintainer alongside the sword
toting @lsm5.

Docker-DCO-1.1-Signed-off-by: Brandon Philips <brandon.philips@coreos.com> (github: philips)
Merge pull request #7090 from philips/add-philips-to-systemd-maintainers

contrib/init/systemd: add philips as MAINTAINER
Merge pull request #7061 from muchweb/rms

Can't believe you forgot RMS
Merge pull request #7050 from Aigeruth/fix/push_image_layer_registry_content_type

Add Content-Type header in PushImageLayerRegistry
Resolve merge conflict, attempt 3

Docker-DCO-1.1-Signed-off-by: AJ Bowen <aj@gandi.net> (github: soulshake)
Merge pull request #6996 from soulshake/patch-1

Update https.md