typo fix in a comment.

git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@2858 e5f2f494-b856-4b98-b285-d166d9295462

src/lib/bench/tests/benchmark_unittest.cc

@@ -58,7 +58,7 @@ BenchMark<TestBenchMark>::tearDown() {
 };
 
 // XXX: some compilers cannot find class static constants used in
-// EXPECT_xxx macross, for which we need an explicit definition.
+// EXPECT_xxx macros, for which we need an explicit definition.
 template <typename T>
 const int BenchMark<T>::TIME_FAILURE;
 }