qemu: QMP capabilities support starts with 1.2

Per the code comment in qemuCapsInitQMPBasic() and commit 43e23c73, we
should only use QMP for capabilities probing starting with 1.2 and
newer.  The old code had dead logic that probed on 1.0 and newer.
Signed-off-by: NEric Blake <eblake@redhat.com>

src/qemu/qemu_capabilities.c

@@ -2314,7 +2314,7 @@ qemuCapsInitQMP(qemuCapsPtr caps,
     VIR_DEBUG("Got version %d.%d.%d (%s)",
               major, minor, micro, NULLSTR(package));
 
-    if (!(major >= 1 || (major == 1 && minor >= 1))) {
+    if (major < 1 || (major == 1 && minor < 2)) {
         VIR_DEBUG("Not new enough for QMP capabilities detection");
         ret = 0;
         goto cleanup;