camcontrol timestamp -s would somtimes fail due to stack garbage. Zero out
the timestamp parameters to fix it.
Fix another nearby bug, and update the man page.
sbin/camcontrol/timestamp.c:
In set_timestamp(), bzero ts_p prior to creating the timestamp.
Previously stack garbage could cause some tape drives to reject the
timestamp.
In set_timestamp(), check for failures from strptime().
sbin/camcontrol/camcontrol.8:
Add the time argument to the -T option to camcontrol timestamp -s
in the long description.
Change the time/date format used in the camcontrol timestamp
example to RFC 2822 format. This fixes a time zone issue with the
original example by specifying the time zone as -0600. Otherwise,
the time zone seems to default to standard time in the current
locale, which makes the time, when reported back from the drive,
1 hour off from the intended setting. This also fixes a duplicate
day of the week ("Wednesday Wed") in the previous example.
Submitted by: Sam Klopsch
MFC after: 3 days
Sponsored by: Spectra Logic
d618624cbd