vmbus_testing: fix wrong python syntax for integer value comparison

vmbus_testing: fix wrong python syntax for integer value comparison

It is incorrect in python to compare integer values using the "is" keyword.
The "is" keyword in python is used to compare references to two objects,
not their values. Newer version of python3 (version 3.8) throws a warning
when such incorrect comparison is made. For value comparison, "==" should
be used.

Fix this in the code and suppress the following warning:

/usr/sbin/vmbus_testing:167: SyntaxWarning: "is" with a literal. Did you mean "=="?

Signed-off-by: Ani Sinha <anisinha@redhat.com>
Link: https://lore.kernel.org/r/20230705134408.6302-1-anisinha@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>