Open shim v2 log with the flag `O_RDWR` will cause the `Read()` block
forever even if the pipe has been closed on the shim side. Then the
`io.Copy()` would never return and lead to a fd leak.
Fix typo when closing shim v1 log which causes the `stdouLog` leak.
Update `numPipes` function in test case to get the opened FIFO
correctly.
Signed-off-by: Li Yuxuan <liyuxuan04@baidu.com>