test: better test port availablility by binding

Port connection test may return true while port was recently used on linux but not fully released.
Binding on port is definitively more reliable as more on the purpose.

t/lib/FusionInventory/Test/Utils.pm

@@ -28,13 +28,13 @@ sub test_port {
     my $paddr = sockaddr_in($port, $iaddr);
     my $proto = getprotobyname('tcp');
     if (socket(my $socket, PF_INET, SOCK_STREAM, $proto)) {
-        if (connect($socket, $paddr)) {
+        if (bind($socket, $paddr)) {
             close $socket;
-            return 0;
+            return 1;
         }
     }
 
-    return 1;
+    return 0;
 }
 
 sub test_localhost {