Fix a -Wparentheses warning from GCC that caught a badly formed assert.
Fix a -Wparentheses warning from GCC that caught a badly formed assert.

I have no idea why Clang's warning doesn't fire here, looks like a Clang
bug. I'll investigate that separately.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@198677 91177308-0d34-0410-b5e6-96231b3b80d8

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