Install gcc in build image
Install gcc in build image

gcc is required to build some packages but isn't required in the spec
file so have it preinstalled.

Change-Id: I9132f8572f61e8bdaae62f7fc41b6fc29ad615e7

openstack-packages/delorean,openstack-packages/DLRN,derekhiggins/delorean_fork,openstack-packages/delorean,openstack-packages/DLRN,derekhiggins/delorean_fork,derekhiggins/delorean_fork