Fix problems where http pulls on windows (win2k) where the probekey output from cmd_pull_part1 was not getting flushed to the client before the socket connection was dropped.
Fix problems where http pulls on windows (win2k) where the
probekey output from cmd_pull_part1 was not getting flushed
to the client before the socket connection was dropped.

bk: 46488baets2pjv9OYotuPRkzDLELuA
bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper