virQEMUCaps: Drop unused usedQMP member

The virQEMUCaps structure has usedQMP member which in the past
used to tell if qemu we are dealing with is capable of QMP. Well,
we don't support HMP anymore (minus a few HMP passthrough
commands, which are wrapped into QMP anyways) and the member is
not used really.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NDaniel Henrique Barboza <danielhb413@gmail.com>

src/qemu/qemu_capabilities.c

@@ -638,7 +638,6 @@ static void virQEMUDomainCapsCacheDispose(void *obj)
 struct _virQEMUCaps {
     virObject parent;
 
-    bool usedQMP;
     bool kvmSupportsNesting;
 
     char *binary;
@@ -1825,7 +1824,6 @@ virQEMUCapsPtr virQEMUCapsNewCopy(virQEMUCapsPtr qemuCaps)
         return NULL;
 
     ret->invalidation = qemuCaps->invalidation;
-    ret->usedQMP = qemuCaps->usedQMP;
     ret->kvmSupportsNesting = qemuCaps->kvmSupportsNesting;
 
     ret->ctime = qemuCaps->ctime;
@@ -4980,7 +4978,6 @@ virQEMUCapsInitQMPMonitor(virQEMUCapsPtr qemuCaps,
 
     qemuCaps->version = major * 1000000 + minor * 1000 + micro;
     qemuCaps->package = g_steal_pointer(&package);
-    qemuCaps->usedQMP = true;
 
     if (virQEMUCapsInitQMPArch(qemuCaps, mon) < 0)
         return -1;