Patch by Slava Semushin <slava.semushin@gmail.com>
Again, this was tested by comparing obj files from a pristine and a patched
source tree against an i386/ALL kernel, and also for src/sbin/fsck_ffs,
src/sbin/fsdb and src/usr.sbin/makefs. Only changes in assert() line numbers
were detected in 'objdump -d' output.
changes the "tickle" model of wdogctl(8), it was modified as well;
while I was in there, I cleaned up the argument parsing.
The code was reviewed by simonb@.