Adding RunIn to run a user specified command in an existing container, wait for it to exit and return the exit code.
RunIn will connect to a user specified Terminal before running the command.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Updated RunIn API to match the new console handling behavior in HEAD.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
'nsinit exec' now uses namespaces.RunIn instead of namespaces.ExecIn.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Fix runin code for nsinit
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Merge pull request #64 from vishh/runin

Adding RunIn to run a user specified command in an existing container.
Add label.InitLabels functioni. Allows generation of labels based on options

This will allow us to do the following with docker.

Customize the way that a labeling system like SELinux will run on a container.

    --label-opt="user:USER"  : Set the label user for the container
    --label-opt="role:ROLE"  : Set the label role for the container
    --label-opt="type:TYPE"  : Set the label type for the container
    --label-opt="level:LEVEL"  : Set the label level for the container
    --label-opt="disabled"  : Turn off label confinement for the container

Since we are passing a list of string options instead of a space separated
string of options, I will change function calls to use InitLabels instead of
GenLabels.  Genlabels interface is Deprecated.

Docker-DCO-1.1-Signed-off-by: Dan Walsh <dwalsh@redhat.com> (github: rhatdan)