avocado.job: Fix return code of stand alone tests

When running stand alone tests, ie, tests without
the avocado runner, I surely do expect they return
exit codes according to wether it passed or failed.

This patch fixed that by making the TestModuleRunner
class to return appropriate return codes from the
Job.run() function.
Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

avocado/job.py

@@ -187,15 +187,16 @@ class TestModuleRunner(object):
                 self.module = getattr(self.module, part)
         else:
             self.module = module
-        url = None
+        self.url = None
         for key, value in self.module.__dict__.iteritems():
             try:
                 if issubclass(value, test.Test):
-                    url = key
+                    self.url = key
             except TypeError:
                 pass
         self.job = Job()
-        if url is not None:
-            self.job.run(urls=[url])
+        if self.url is not None:
+            sys.exit(self.job.run(urls=[self.url]))
+        sys.exit(error_codes.numeric_status['AVOCADO_ALL_OK'])
 
 main = TestModuleRunner