replace last instances of close()

replace last instances of close()

I am replacing the last instances of close() I found with VIR_CLOSE() / VIR_FORCE_CLOSE respectively.

The first part patches virsh, which I missed out on previously.

The 2nd patch I had left out intentionally to look at it more carefully:
The 'closed' variable could be easily removed since it wasn't used anywhere else. The possible race condition that could result from the filedescriptor being closed and not set to -1 (and possibly let us write into 'something' totally different if the fd was allocated by another thread) seems to be prevented by the qemuMonitorLock() already placed around the code that reads from or writes to the fd. So the change of this code as shown in the patch should not have any side-effects.