Tests: 'Fix' __del__ in test/remote_test.py.

Tests: 'Fix' __del__ in test/remote_test.py.

This is not a fix as much as supressing a warning.
__del__ is not a destructor.

test/remote_test.py:385:13: F821 undefined name 'cls'
            cls.vpp.poll()
            ^
test/remote_test.py:386:16: F821 undefined name 'cls'
            if cls.vpp.returncode is None:
               ^
test/remote_test.py:387:17: F821 undefined name 'cls'
                cls.vpp.terminate()
                ^
test/remote_test.py:388:17: F821 undefined name 'cls'
                cls.vpp.communicate()

Change-Id: I6f0ecf3ae5dee7f279a4e25994cc1c49470bca26
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>