cron: log when a crontab path is too long

[chris.longros_gmail.com]

Summary

Log via syslog when snprintf truncates the crontab path,
instead of silently skipping the entry.

Signed-off-by: Christos Longros <[e-mail]>

[kevans]

Is it safe to assume that I don't want to ask if there's a story behind deciding to resolve this XXX? =) Will try to commit later today

[michaelo]

usr.sbin/cron/cron/database.c

172

Is the length actually documented in the manpage? I fail to find it.

[chris.longros_gmail.com]

usr.sbin/cron/cron/database.c

172

No, there's no documented limit on crontab filename length in cron.8, crontab.1, or crontab.5

[michaelo]

usr.sbin/cron/cron/database.c

172

It think it is then worth documenting that tabname is confined by MAXPATHLEN sans NULL byte.

[chris.longros_gmail.com]

Document the resulting filename length limit in cron(8) under FILES.

[bcr]

OK from manpages.