Prepare to build installer 2.3.1.
Don't copy the lib/FusionInventory/Agent/Tools/SNMP.pm file.

The lib/FusionInventory/Agent/Tools/SNMP.pm file has been removed in commit
a8168b2418.

See https://github.com/fusinv/fusioninventory-agent/commit/a8168b2418ac514c154
5217286f859ceb9149100 for more information.
Improve the help.