load FusionInventory::Test::Agent first

For some mysterious reason, if Test::Agent is loaded after HTTP::Server, method dispatch is broken, and getTargets() method isn't found.

See-also: commit:dd4e4bd
drop flag NIx_NOSERV usage

It is not available in earlier Socket::GetAddrInfo version, and its interest
isn't explicit.

See-also: commit:fe16fee