Updating hwintf test to call host.stop()

host.terminate() does not remove the interfaces

.travis.yml

@@ -7,7 +7,7 @@ before_install:
 - sudo apt-get install -qq vlan
 
 install:
-- sudo util/install.sh -a
+- sudo util/install.sh -fnvw
 
 script:
 - sudo mn --test pingall

examples/test/test_hwintf.py

@@ -57,8 +57,8 @@ class testHwintf( unittest.TestCase ):
         p.wait()
 
     def tearDown( self ):
-        self.h3.terminate()
-        self.n0.terminate()
+        self.h3.stop( deleteIntfs=True )
+        self.n0.stop( deleteIntfs=True )
 
 if __name__ == '__main__':
     setLogLevel( 'warning' )