devmapper: add missing defines

Add some missing defines which are needed for compiling on older systems
like RHEL 6.
Enable engine to take Stderr and Stdout for mocking in tests
specific kernel config
use mattdm/fedora in fedora doc and other cosmetic changes

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
yum upgrade on fedora not required before install

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
add unofficial header back, yum update docker

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
separate block for yum update docker

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
change the policy wrt $ sudo docker to simplify auto-testing
Engine: new command 'kill' sends a signal to a running container
Hack: use new 'kill' command in integration tests
gofmt
Engine: port 'kill' to the new integer status.