OpenBSD prior to 6.3 required a workaround to utilize fcntl(F_SETFL) on memory
devices.

Since modern verions of OpenBSD that are only officialy supported and buildable
on do not have this issue I am garbage collecting this workaround.

Signed-off-by: Brad Smith <brad@comstyle.com>

Message-Id: <YGYECGXQhdamEJgC@humpty.home.comstyle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>