Fix unit tests on CI to not timeout even if POST fails

Specifically, POST-ing the test results in xUnit format to the trivial
Node server that's supposed to collect them; if something went wrong
with the trivial Node server (like in the previous 2 commits), we
shouldn't hang, we should still tell Sauce the test results (and that
the tests are done).
diff --git a/test/unit.html b/test/unit.html
index 04fb3b6..601820c 100644
--- a/test/unit.html
+++ b/test/unit.html
@@ -78,7 +78,7 @@
 
         runner.on('end', function() {
           setTimeout(function() {
-            $.post(post_xunit_to, xunit, function() {
+            $.post(post_xunit_to, xunit).always(function() {
               window.mochaResults = runner.stats;
               window.mochaResults.reports = failedTests;
             });