When dispatching events from the event loop, the array of registered
handles is searched to see what handles happened an event on. However,
the array is searched in weird way: the check for the array boundaries
is at the end, so we may touch the elements after the end of the
array:

==10434== Invalid read of size 4
==10434==    at 0x52D06B6: virEventPollDispatchHandles (vireventpoll.c:486)
==10434==    by 0x52D10E4: virEventPollRunOnce (vireventpoll.c:660)
==10434==    by 0x52CF207: virEventRunDefaultImpl (virevent.c:308)
==10434==    by 0x1639D1: virNetServerRun (virnetserver.c:1139)
==10434==    by 0x1220DC: main (libvirtd.c:1507)
==10434==  Address 0xc11ff04 is 4 bytes after a block of size 960 alloc'd
==10434==    at 0x4C2CA5E: realloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==10434==    by 0x52AD378: virReallocN (viralloc.c:245)
==10434==    by 0x52AD46E: virExpandN (viralloc.c:294)
==10434==    by 0x52AD5B1: virResizeN (viralloc.c:352)
==10434==    by 0x52CF2EC: virEventPollAddHandle (vireventpoll.c:116)
==10434==    by 0x52CEF5B: virEventAddHandle (virevent.c:78)
==10434==    by 0x11F69A90: nodeStateInitialize (node_device_udev.c:1797)
==10434==    by 0x53C3C89: virStateInitialize (libvirt.c:743)
==10434==    by 0x120563: daemonRunStateInit (libvirtd.c:919)
==10434==    by 0x5317719: virThreadHelper (virthread.c:197)
==10434==    by 0x8376F39: start_thread (in /lib64/libpthread-2.17.so)
==10434==    by 0x8A7F9FC: clone (in /lib64/libc-2.17.so)
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>