Fix condition in BlockIO test
Fix condition in BlockIO test

Symptoms:
```
$ sudo validation/linux_cgroups_relative_blkio.t

 not ok 6 - blkio leafWeight for 8:0 is set correctly
 # expect: 300, actual: 300
```

After the patch:
```
 ok 6 - blkio leafWeight for 8:0 is set correctly
 # expect: 300, actual: 300
```

Signed-off-by: Alban Crequy <5d61c11e6df8ed8ffd2a3627a86b97e825765970@kinvolk.io>

wking/ocitools-v2,opencontainers/ocitools,liangchenye/ocitools,liangchenye/ocitools,opencontainers/runtime-tools,opencontainers/runtime-tools,opencontainers/ocitools,wking/ocitools-v2