Log Message:
Do not install bin/ftp (this will overwrite the ftp installed as part
of bootstrap-pkgsrc).

ftp is now always installed as bin/k4ftp. In addition, if the variable
KRB4_PREFIX_CMDS is set to YES, rcp, rlogin, rsh, su, and telnet will
be installed with a "k4" prefix.

This has been achieved by stealing the transform code from security/heimdal
and by tayloring it a bit.

Closes PR pkg/24354 by Tracy Di Marco White.