Extract DCV packages in the sources folder and not in a temporary one

The chef cache path is not available in the dcv_config recipe if the
extraction of DCV packages is performed at AMI creation time.

By using sources dir we are sure to have them at runtime.

Signed-off-by: Enrico Usai <usai@amazon.com>

Author: Enrico Usai

recipes/dcv_config.rb

@@ -34,7 +34,7 @@ def allow_gpu_acceleration
   end
 
   # dcvgl package must be installed after NVIDIA and before starting up X
-  dcv_gl = "#{Chef::Config[:file_cache_path]}/#{node['cfncluster']['dcv']['package']}/#{node['cfncluster']['dcv']['gl']}"
+  dcv_gl = "#{node['cfncluster']['sources_dir']}/#{node['cfncluster']['dcv']['package']}/#{node['cfncluster']['dcv']['gl']}"
   package dcv_gl do
     action :install
     source dcv_gl

recipes/dcv_install.rb

@@ -91,7 +91,7 @@ def disable_lock_screen
       end
 
       bash 'extract dcv packages' do
-        cwd Chef::Config[:file_cache_path]
+        cwd node['cfncluster']['sources_dir']
         code "tar -xvzf #{dcv_tarball}"
       end
     end