Fix minor memory leak in klist (again)

[No urgency on this one; it's not for pullup to 1.13.  Found with Coverity Scan.]

Commit 6e51f9cc3152c8e419fe7f459bcf521d60358434 attempted to fix two
minor memory leaks in klist, but one of the fixes was dead code.  In
do_ccache, free princ before we look at the code which terminated the
loop, not after we have returned on either branch.