Remove ocveralls from the OPAM file
Remove ocveralls from the OPAM file

It's not needed for the build, and is explicitly installed by the
coverage script.

Signed-off-by: John Else <37b74501daa612e48fea94f9846ed4ddeb6a8f07@citrix.com>

djs55/message-switch-1,djs55/message-switch,djs55/message-switch-1,xapi-project/message-switch,xapi-project/message-switch,djs55/message-switch,djs55/message-switch-1,djs55/message-switch,xapi-project/message-switch