RX: Add rx_InterruptCall

RX: Add rx_InterruptCall

Add rx_InterruptCall, to cause a call to error out and wakeup anyone
waiting to write or read to that call.

Change-Id: I0747ac9107dac6b9a6d8b8c59120a756416aad58
Reviewed-on: http://gerrit.openafs.org/2982
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Tom Keiser <tkeiser@sinenomine.net>
Tested-by: Derrick Brashear <shadow@dementia.org>