log: do not log if QEMU is daemonized but without -D
Commit
96c33a4 ("log: Redirect stderr to logfile if deamonized",
2016-02-22) wanted to move stderr of a daemonized QEMU to the file
specified with -D.
However, if -D was not passed, the patch had the side effect of not
redirecting stderr to /dev/null. This happened because qemu_logfile
was set to stderr rather than the expected value of NULL. The fix
is simply in the "if" condition of do_qemu_set_log; the "if" for
closing the file is also changed to match.
Reported-by: Jan Tomko <jtomko@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>