fixup: also change missed openvpn_sleep() occurrences

fixup: also change missed openvpn_sleep() occurrences

45b2af9c missed some openvpn_sleep() occurrences in platform-specific code
in tun.c - fix that.

Signed-off-by: Steffan Karger <steffan@karger.me>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1500578222-21689-1-git-send-email-steffan@karger.me>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15111.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit cdb262a6c78a29349789b7cf1813feaf7cc6e8c8)