ovs-ctl.in: Set hard limit for core files created.

ovs-ctl.in: Set hard limit for core files created.

Currently we set a soft limit while defining the maximum size of
core files. If there is already a hard limit set that is lesser
than the soft limit we are setting, it will fail.

Since our startup scripts start with root permissions, it looks
fine to set the hard limit directly instead.

Reported-by: Dan Wendlandt <dan@nicira.com>
Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>