s3:notifyd: Handle sigup in notifyd to reparse smb.conf

s3:notifyd: Handle sigup in notifyd to reparse smb.conf

At present, SIGHUP is blocked on notifyd. So, if parent smbd
is started with "log level" 10 in smb.conf, and later changed
to 0, the SIGHUP will not change the log level to 0 in notify
smbd process and it will keep printing verbose logs in the
corresponding log files.

Proposed fix is to write a SIGHUP handler for notifyd and set
it to reload services.

Reviewed-by: Hemanth Thummala <hemanth.thummala@nutanix.com>
Signed-off-by: Shyamsunder Rathi <shyam.rathi@nutanix.com>
Reviewed-by: Jeremy Allison <jra@samba.org>
Reviewed-by:Volker Lendecke <vl@samba.org>

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Thu Jun 27 17:57:12 UTC 2019 on sn-devel-184