Project name mismatch

Here's my upstart config file (/etc/init/fig.conf) I use to run fig after docker starts and stop fig before docker stops.

	description "Fig daemon"

	start on started docker
	stop on stopping docker

	kill signal SIGINT  # upstart uses SIGTERM as default, critical for graceful shutdown
	chdir /path/to/dir/containing/config # avoid project name bug
	exec /usr/local/bin/fig -f /path/to/dir/containing/config/fig.yml up 2>&1  # redirect stderr to the log file (/var/log/upstart/fig.log)

The `chdir` is only necessary so that the project name is set correctly as the `-f` arg isn't taken into account. Without it the project name defaults to `default` and then `fig` commands don't work as the project name mismatch means that no containers are found, even though containers can be seen with `docker ps`.

This patch creates the project name from the directory that fig.yml is in, whether provided via `-f` or implicit.