SOLARIS: Correct ioctl syscall error handling

SOLARIS: Correct ioctl syscall error handling

Do not use the return code from ioctl for errno. Ioctl itself will set
the errno and return value correctly, so don't mess with them.

Change-Id: I26c3afb5c77a3fce57e0d53d8671541805b32e08
Reviewed-on: http://gerrit.openafs.org/4345
Tested-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@dementia.org>