[krbdev.mit.edu #3313] doublefree in gc_frm_kdc.c

[Jeffrey Altman via RT]

Here is a revision to tom's latest patch.  I am more comfortable with
testing the 'free_tgt' and 'free_otgt' variables and freeing the data
structures at the time we need to replace the value instead of
attempting to make sure that we always clean up after the code as soon
as we think we might be done to put things into the correct state for
later re-use.

I have verified that all of the 'tgt', 'otgt', 'tgtq' and 'tgtr'
variables are appropriately initialized and freed regardless of the
error states.

Jeffrey Altman