maint: fix typo in qemu error message

Introduced in commit d47eff88.

* src/qemu/qemu_driver.c (qemuDomainSetVcpusFlags): Fix spelling.
Signed-off-by: NEric Blake <eblake@redhat.com>

src/qemu/qemu_driver.c

@@ -4133,7 +4133,7 @@ qemuDomainSetVcpusFlags(virDomainPtr dom, unsigned int nvcpus,
     if (flags & VIR_DOMAIN_VCPU_GUEST) {
         if (flags & VIR_DOMAIN_AFFECT_CONFIG) {
             virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
-                           _("chainging of maximum vCPU count isn't supported "
+                           _("changing of maximum vCPU count isn't supported "
                              "via guest agent"));
             goto endjob;
         }