Treat Clock and Random modules as 'devices'

We want the user to specify Clock and Random 'devices' in their
configuration so that the appropriate packages are linked in. However
these 'devices' don't have a 'connect' method, so replace with a
'return (`Ok ())'

Fixes #289

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #290 from djs55/clock-random

Treat Clock and Random modules as 'devices'