validate:launcher: Use the number of failed test as exit code

We used to always return 0, which was not right!

validate/launcher/baseclasses.py

@@ -1680,7 +1680,7 @@ class _TestsLauncher(Loggable):
             return self._run_tests()
 
     def final_report(self):
-        self.reporter.final_report()
+        return self.reporter.final_report()
 
     def needs_http_server(self):
         for tester in self.testers:

validate/launcher/main.py

@@ -594,11 +594,11 @@ Note that all testsuite should be inside python modules, so the directory should
         exception = e
         pass
     finally:
-        tests_launcher.final_report()
+        res = tests_launcher.final_report()
         tests_launcher.clean_tests()
         httpsrv.stop()
         vfb_server.stop()
         if exception is not None:
             raise exception
 
-    return 0
+    return res

validate/launcher/reporters.py

@@ -125,6 +125,8 @@ class Reporter(Loggable):
 
         printc("%sTotal: %d" % (lenstat * " ", total), color)
 
+        return self.stats["failures"]
+
 
 class XunitReporter(Reporter):
 
@@ -139,7 +141,7 @@ class XunitReporter(Reporter):
 
     def final_report(self):
         self.report()
-        super(XunitReporter, self).final_report()
+        return super(XunitReporter, self).final_report()
 
     def _get_captured(self, test):
         captured = ""