sockfilt: fix broken pipe on Windows to be ready in select_ws

Closes #5228
diff --git a/tests/server/sockfilt.c b/tests/server/sockfilt.c
index 166b75b..60ee07f 100644
--- a/tests/server/sockfilt.c
+++ b/tests/server/sockfilt.c
@@ -544,14 +544,17 @@
             }
           }
           else {
-            /* if the pipe has been closed, sleep and continue waiting */
+            /* if the pipe has NOT been closed, sleep and continue waiting */
             length = GetLastError();
-            logmsg("[select_ws_wait_thread] PeekNamedPipe error: %d", length);
-            if(length == ERROR_BROKEN_PIPE) {
+            if(length != ERROR_BROKEN_PIPE) {
+              logmsg("[select_ws_wait_thread] PeekNamedPipe err: %d", length);
               SleepEx(0, FALSE);
               ReleaseMutex(mutex);
               continue;
             }
+            else {
+              logmsg("[select_ws_wait_thread] pipe closed, PIPE: %p", handle);
+            }
           }
           /* there is some data available, stop waiting */
           logmsg("[select_ws_wait_thread] data available, PIPE: %p", handle);