Add an explicit dependency on oclock

Previously we got this transitively from xcp-idl -> message-switch but
the latest version of message-switch doesn't use it anymore.

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Merge pull request #21 from robhoes/master

Add an explicit dependency on oclock
Release 0.9.8

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #22 from djs55/release.0.9.8

Release 0.9.8