make sccs_get() output the value of a symlink target when in PRINT mode. rework mode update code.
make sccs_get() output the value of a symlink target
when in PRINT mode.
rework mode update code.

bk: 372e1181mmn0_LnKw0ycUu7wovMPew
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