Fix CHush test

Fix CHush test

The compiler flagged this with a warning, and depending on the
flags that are set, the test may not give the expected result.

Use parentheses to get the intended precedence.

Change-Id: If0311aae70d6e71b69e247e5b66e0dd558c2c958
Reviewed-on: http://gerrit.openafs.org/2232
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>