auth/authcon.c: fix likely mistake

It seems likely the original developer intended to check
*scIndex==RX_SECIDX_NULL rather than scIndex==RX_SECIDX_NULL.

Change-Id: I8a33d3cb177a9212917613581957073392b08314
Reviewed-on: http://gerrit.openafs.org/8881
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Simon Wilkinson <simonxwilkinson@gmail.com>
butm/file_tm.c: check for null pointer before dereferencing

Move the null pointer check to before the pointer is dereferenced.

Change-Id: I9983dae8802706c1efeff8a507a001b649572686
Reviewed-on: http://gerrit.openafs.org/8882
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
lwp/iomgr.c: avoid off-by-one out-of-bounds access

Avoid accessing sigDelivered[NSIG] and sigEvents[NSIG], which are
out-of-bounds by one.

Change-Id: Id6a1798cba901987b8103f287e0869b31040b45b
Reviewed-on: http://gerrit.openafs.org/8883
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>