CentOS - May 2015 - VNC Server Centos 7 specify window manager

I have a simple question, how do I specify a gnome session with VNc 
Server. I correctly setup up the connections but when I log in all I get 
is a blue screen with a checkbox in the upper left corner saying "Accept 
clipboard from viewers".

My guess is that I am loading generuc X11 by default. How do I specify in 
the etc/systemd/system/vncserver@:4.service file that I want it to load 
gnome?

I tried editing my .vnc/xstartup file but that seems to have no effect.

my xstartup file

#!/bin/sh

exec gnome-session &
~

Never mind. I tried it again and it worked with just the gnome-session in 
the xstartup file.