Functional test setup steps for developers guide

Change-Id: I86c562d555c402a5e3ce3ce471a40d872de8bdce
Signed-off-by: Chetan Risbud <crisbud@redhat.com>
Reviewed-on: http://review.gluster.org/5292
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>