Handle errors from curs_init in db2 back end

ctx_iterate could ignore errors from curs_init.  Actually pass them up
to the caller.

https://github.com/krb5/krb5/commit/da4447bd3a9e12485cf2e6cc925dcc386585a0c1
Author: Tom Yu <tlyu@mit.edu>
Commit: da4447bd3a9e12485cf2e6cc925dcc386585a0c1
Branch: master
 src/plugins/kdb/db2/kdb_db2.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)