Allow BK_STDIO=host:port to mean to connect to that socket and plum that socket into stdin/stdout.  Similarly for BK_STDERR. Set BK_STDIO=DONE so that we don't keep doing this in subprocesses. Fixed one more time to handle stderr independently.
Allow BK_STDIO=host:port to mean to connect to that socket and
plum that socket into stdin/stdout.  Similarly for BK_STDERR.
Set BK_STDIO=DONE so that we don't keep doing this in subprocesses.
Fixed one more time to handle stderr independently.

bk: 41852670jGuPEbaYuySNyycNFkmP6A
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