build: fix qemuagenttest build with -O0 in fedora 19.

build: fix qemuagenttest build with -O0 in fedora 19.

When building libvirt with -O0 flag in fedora 19, it will fail to
generate qemuagenttest, a link error occurs like:

./.libs/libqemumonitortestutils.a(qemumonitortestutils.o): In function `qemuMonitorTestFree':
libvirt/tests/qemumonitortestutils.c:346: undefined reference to `qemuMonitorClose'
./.libs/libqemumonitortestutils.a(qemumonitortestutils.o): In function `qemuMonitorTestNew':
libvirt/tests/qemumonitortestutils.c:870: undefined reference to `qemuMonitorOpen'
collect2: error: ld returned 1 exit status

Fix it by listing libraries in the correct order to avoid lazy linkage.

Signed-off-by: Eric Blake <eblake@redhat.com>