kvm: nVMX: Don't set vmcs12 to "launched" when VMLAUNCH fails

The VMCS launch state is not set to "launched" unless the VMLAUNCH
actually succeeds. VMLAUNCH failure includes VM-exits with bit 31 set.

Note that this change does not address the general problem that a
failure to launch/resume vmcs02 (i.e. vmx->fail) is not handled
correctly.

Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>