Fix memory leak in DB2 iteration

Use the correct function to free the decoded principal entry in
curs_run_cb().

[ghudson@mit.edu: commit message]

https://github.com/krb5/krb5/commit/527edfaadb648a0dd2a42cd39a5a02a4ac37d7e3
Author: Pavel Jindra <paja@civ.zcu.cz>
Committer: Greg Hudson <ghudson@mit.edu>
Commit: 527edfaadb648a0dd2a42cd39a5a02a4ac37d7e3
Branch: master
 src/plugins/kdb/db2/kdb_db2.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)