[libvirt] 'make check' hangs

[Wen Congyang]

When I run 'make check', it hangs sometimes.

I use gdb to attach lt-virsh, and the following is the
backtrace:
(gdb) thread 1
[Switching to thread 1 (Thread 0x7fc6c04d5800 (LWP 24099))]#0  0x0000003bdce0804d in pthread_join () from /lib64/libpthread.so.0
(gdb) bt
#0  0x0000003bdce0804d in pthread_join () from /lib64/libpthread.so.0
#1  0x000000000041c0b3 in vshDeinit (ctl=0x7fff015f4570) at virsh.c:17262
#2  0x00000000004248d1 in main (argc=<value optimized out>, argv=0x7fff015f4728) at virsh.c:17608
(gdb) thread 2
[Switching to thread 2 (Thread 0x7fc6c04d4700 (LWP 24138))]#0  0x0000003bdc2dc053 in poll () from /lib64/libc.so.6
(gdb) bt
#0  0x0000003bdc2dc053 in poll () from /lib64/libc.so.6
#1  0x00007fc6c075359c in virEventPollRunOnce () at util/event_poll.c:619
#2  0x00007fc6c07527d7 in virEventRunDefaultImpl () at util/event.c:247
#3  0x000000000041bea3 in vshEventLoop (opaque=0x7fff015f4570) at virsh.c:16800
#4  0x00007fc6c0764702 in virThreadHelper (data=<value optimized out>) at util/threads-pthread.c:157
#5  0x0000003bdce077f1 in start_thread () from /lib64/libpthread.so.0
#6  0x0000003bdc2e570d in clone () from /lib64/libc.so.6
(gdb)