Fix assert message to avoid printing garbage

Fix assert message to avoid printing garbage

Fix an off by one error in assert() to avoid printing garbage
characters to the log. Remove the newline character generated by
ctime() to match the format generated by the other logging functions.

FIXES 124613

Reviewed-on: http://gerrit.openafs.org/102
Verified-by: Russ Allbery <rra@stanford.edu>
Reviewed-by: Russ Allbery <rra@stanford.edu>
(cherry picked from commit 15d203c7be957ba0e63288e2d95cbd078d94eb21)
Change-Id: I4720285db68f30730f67d62978d777fd6857fc7a
Reviewed-on: http://gerrit.openafs.org/931
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>