Kerberos no longer prerequires rsh to build succesfully (krb5-1.3.1).
It builds succesfully without rsh installed on the system. Please
remove this BuildPrereq from the spec file.
How have you determined this? The src/appl/bsd/configure script still
guesses that rsh is installed as /usr/ucb/rsh if rsh is not found at
compile-time. Marking won't fix because it's still needed for this
test to determine the correct path.