Open PLAP debug file in unicode mode

_wfopen requires ccs=<encoding> to support writing of
non-ascii text. This was missed in the initial commit.

Signed-off-by: Selva Nair <selva.nair@gmail.com>

plap/plap_common.c

@@ -37,7 +37,7 @@ void
 init_debug()
 {
     if (!fp)
-        fp = _wfopen(L"C:\\Windows\\Temp\\openvpn-plap-debug.txt", L"a+");
+        fp = _wfopen(L"C:\\Windows\\Temp\\openvpn-plap-debug.txt", L"a+,ccs=UTF-8");
     InitializeCriticalSection(&log_write);
 }