qemu_process: Accept VIR_QEMU_PROCESS_START_RESET_NVRAM flag when starting a domain

qemu_process: Accept VIR_QEMU_PROCESS_START_RESET_NVRAM flag when starting a domain

In one of my previous commits I've fixed the value of
VIR_QEMU_PROCESS_START_RESET_NVRAM flag (which was masking
another value). But what I forgot to do is update virCheckFlags()
calls in two places where the flag is passed: qemuProcessLaunch()
and qemuProcessStart().

Fixes: 1b636593c76f443169ef7bdb3644fd670379d04e
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>