message: Fix capacity check in BufAccessor test
  Summary:
  IOBuf creates a buffer that has the capacity GE the input capacity.
  (Note: this ignores all push blocking failures!)
diff: @@ -14,7 +14,7 @@ TEST(SimpleBufAccessor, BasicAccess) {
  SimpleBufAccessor accessor(1000);
  EXPECT_TRUE(accessor.ownsBuffer());
  auto buf = accessor.obtain();
  - EXPECT_EQ(1000, buf->capacity());
  + EXPECT_LE(1000, buf->capacity());
  EXPECT_FALSE(accessor.ownsBuffer());
  auto empty = accessor.obtain();
  EXPECT_EQ(nullptr, empty);
  