Remove reference to nsinit

Signed-off-by: Antonio Murdaca <runcom@linux.com>

.gitignore

@@ -1,4 +1,2 @@
-bundles
-nsinit/nsinit
 vendor/pkg
 runc

libcontainer/docs/man/nsinit.1.md

@@ -1,38 +0,0 @@
-% nsinit User Manual
-% opencontainers/runc/libcontainer
-% JAN 2015
-
-NAME:
-   nsinit - A low-level utility for managing containers.
-	    It is used to spawn new containers or join existing containers.
-
-USAGE:
-   nsinit [global options] command [command options] [arguments...]
-
-VERSION:
-   0.1
-
-COMMANDS:
-	config	display the container configuration 
-	exec	execute a new command inside a container
-	init	runs the init process inside the namespace
-	oom	display oom notifications for a container
-	pause	pause the container's processes
-	stats	display statistics for the container
-	unpause	unpause the container's processes
-	help, h	shows a list of commands or help for one command
-
-EXAMPLES:
-
-Get the <container_id> of an already running docker container.
-`sudo docker ps` will return the list of all the running containers.
-
-take the <container_id> (e.g. 4addb0b2d307) and go to its config directory
-`/var/lib/docker/execdriver/native/4addb0b2d307` and here you can run the nsinit
-command line utility.
-
-e.g. `nsinit exec /bin/bash` will start a shell on the already running container.
-   
-# HISTORY
-Jan 2015, Originally compiled by Shishir Mahajan (shishir dot mahajan at redhat dot com)
-based on nsinit source material and internal work.