Fix a case where merging in csets created before the last tag can cause tclkey.h to use a different hash even when nothing changed.  This causes the tcl/tk binaries to be rebuilt way too often.  Especially around the time were are making new releases.
Fix a case where merging in csets created before the last
tag can cause tclkey.h to use a different hash even when
nothing changed.  This causes the tcl/tk binaries to be
rebuilt way too often.  Especially around the time
were are making new releases.

BTW: This is caused by a subtle bug in bk-4.1.1 and later
     where makepatch can order files in a cset.
     (Still correct, but different)

bk: 484437d5Rl6hbV-DvZgwDsxUVj7rVA
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