Call krb5_klog_reopen in kadm_svc_run upon receiving a SIGHUP. Use

Call krb5_klog_reopen in kadm_svc_run upon receiving a SIGHUP.  Use
sigaction instead of signal if POSIX_SIGNALS is defined.  All of the
calls to signal and sigaction are now in a separate function
setup_signal_handlers, as the kdc code does.  Also, since reset_db no
longer does anything, change the name of signal_request_reset to the
more descriptive signal_request_hup, and request_reset_db to
request_hup (paralleling the nomenclature in the kdc code).

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@10712 dc483132-0cff-0310-8789-dd5450dbe970