fix return check for KVM_GET_DIRTY_LOG ioctl

Fix return condition check from kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) to
handle internal failures or no support for memory slot dirty bitmap.
Otherwise the ioctl succeeds and continues with migration.
Addresses BUG# 1294227

Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

kvm-all.c

@@ -441,7 +441,7 @@ static int kvm_physical_sync_dirty_bitmap(MemoryRegionSection *section)
 
         d.slot = mem->slot;
 
-        if (kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) == -1) {
+        if (kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) < 0) {
             DPRINTF("ioctl failed %d\n", errno);
             ret = -1;
             break;