[krbdev.mit.edu #8363] s4u protocol transition tests revealing memleaks in krb5kdc

[Will Fiveash via RT]

I'm seeing a number of memory leaks affecting krb5kdc when the t_s4u.py
test is run.  Here are the typical leaked memory allocation stacks:

umem_alloc_112 leak: 12 buffers, 112 bytes each, 1344 bytes total
            ADDR          BUFADDR        TIMESTAMP           THREAD
                            CACHE          LASTLOG         CONTENTS
      cfeef635f0       cfeef60fd0   4e024ede49f9ab                1
                       cfeee3c028       cfeec41b00                0
                 libumem.so.1`umem_cache_alloc+0x158
                 libumem.so.1`umem_alloc+0x70
                 libumem.so.1`malloc+0x24
                 libumem.so.1`calloc+0x44
                 db2.so`krb5_decode_princ_entry+0xc
                 db2.so`krb5_db2_get_principal+0xf8
                 db2.so`wrap_krb5_db2_get_principal+0x34
                 libkdb5.so.8.0`krb5_db_get_principal+0x50
                 kdc_get_server_key+0x58
                 process_tgs_req+0x75c
                 dispatch+0x298
                 krb5kdc`process_tcp_connection_read+0x21c
                 libverto.so.0.0`verto_fire+0x28
                 libverto.so.0.0`k5ev_invoke_pending+0x54
                 libverto.so.0.0`k5ev_run+0x464

and

umem_alloc_64 leak: 12 buffers, 64 bytes each, 768 bytes total
            ADDR          BUFADDR        TIMESTAMP           THREAD
                            CACHE          LASTLOG         CONTENTS
      cfeef1feb0       cfeef1af80   4e024ede4a1210                1
                       cfeee2e028       cfeec41bc0                0
                 libumem.so.1`umem_cache_alloc+0x228
                 libumem.so.1`umem_alloc+0x70
                 libumem.so.1`malloc+0x24
                 libumem.so.1`calloc+0x44
                 libkrb5.so.3.3`allocate_princ+0x10
                 libkrb5.so.3.3`krb5_parse_name_flags+0x30
                 db2.so`krb5_decode_princ_entry+0x368
                 db2.so`krb5_db2_get_principal+0xf8
                 db2.so`wrap_krb5_db2_get_principal+0x34
                 libkdb5.so.8.0`krb5_db_get_principal+0x50
                 kdc_get_server_key+0x58
                 process_tgs_req+0x75c
                 dispatch+0x298
                 krb5kdc`process_tcp_connection_read+0x21c
                 libverto.so.0.0`verto_fire+0x28

I've attached the full memleak report.