Remove old tarball before moving the new archive to /data.

Ticket: #4581
Exclude itself from list while editing sysctl

It was preventing sysctl edit.

Ticket:	#4516
Our UPS daemon (nut) runs as uucp:uucp so make sure that it can write
the log.

Ticket: #4575
Add alert module to warn about failed replication

Ticket:	#4553
Move repl_enabled field to the end

This will show it as the last field in replication datagrid.
Fix alert level
Strip new lines for the replication status

Ticket:	#4553
Show whether the snapshot is already in remote side

Ticket:	#4553
Do not store last replication result in the database

Ticket:	#4553
repl_lastresult is not a field in the ORM anymore

Ticket:	#4553
Do not run ssh in quiet mode to retrieve errors

Ticket:	#4553
Use a connect timeout in ssh for replication

It is an arbitrary value without any scientific comprovation :).
That is the easiest way to do not hang in "Sending" status when it is
not actually doing it.

Ticket:	#4553
Fix UPS driver list reader to exclude comments

Ticket:	#4567
Bail out when doing make release if the environment isn't checked out.

This makefile is starting to get ugly.  Reminds me of the build system
three years ago.

We should circle the wagons before too long.
Warn about a few other tools which are needed to build FreeNAS.

This helps people (like me!) who set up new build environments for FreeNAS,
but don't read all the instructions about what tools must be installed
before typing 'make'.