Adding Sherif to adm group on sa497-crunch machines

Signed-off-by: Thomas Bytheway <tb403@cam.ac.uk>
Moved sherif's user definition entirely to sa497-crunch.pp

Signed-off-by: Thomas Bytheway <tb403@cam.ac.uk>
Merge branch 'master' of puppy23.dtg.cl.cam.ac.uk:/etc/puppet-bare

Conflicts:
	manifests/globals.pp