Remove vestigial 3DFS support code (re: f88f302c)

Support for the long-dead 3DFS userland versioning file system was
already removed from ksh93 (although I'd overlooked some minor
things), but libast still supported it. This removes that too.

src/lib/libast/include/fs3d.h,
src/lib/libast/man/fs3d.3,
src/lib/libast/misc/fs3d.c:
- Removed.

bin/package,
src/cmd/INIT/package.sh:
- Remove attempted use of removed vpath builtin.

src/cmd/ksh93/*:
- Remove minor 3dfs vestiges.

src/lib/lib{ast,cmd,coshell}/*:
- Remove code supporting 3dfs.

src/cmd/ksh93/data/builtins.c

@@ -2030,11 +2030,6 @@ _JOB_
 "[+SEE ALSO?\bjobs\b(1), \bps\b(1)]"
 ;
 
-#if SHOPT_FS_3D
-    const char sh_optvpath[]	= " [top] [base]";
-    const char sh_optvmap[]	= " [dir] [list]";
-#endif /* SHOPT_FS_3D */
-
 const char sh_optwhence[] =
 "[-1c?\n@(#)$Id: whence (AT&T Research) 2007-04-24 $\n]"
 USAGE_LICENSE