Description of problem:
After upgrading from krb5(1.3.4-27) to krb5(1.3.4-33), when using ksu and
exiting, the user gets the error :
--
[krb_user@dhcp-0-190 root]$ exit
exit
ksu: Operation not permitted while returning to source uid for destroying ccache
--
Checking on the source code, we can see this failure reported in
src/client/ksu/main.c [void sweep_up()]. There is there a condition that is not
right :

       if (krb5_seteuid(0) < 0 || krb5_seteuid(target_uid) < 0) {

In fact, seteuid(0) will always fail here unless we are root, or maybe under
other circunstances. After more researches, I've found the following :

* http://mailman.mit.edu/pipermail/kerberos/2006-August/010276.html

Which presents the same solution as the patch attached and seems committed to
1.5.1 too (haven't checked yet).

The solution would be to remove krb5_seteuid(0); from the loop, and if it fails
let it fail silently as we know it will on some circunstances, it is true,
though, that krb5_seteuid(target_uid) *has* to be monitored and has to exit if
failure.

Version-Release number of selected component (if applicable):
1.3.4-33

How reproducible:
Always.

Steps to Reproduce:
1. ksu krb_user
2. exit
  
Actual results:
--
[krb_user@dhcp-0-190 root]$ exit
exit
ksu: Operation not permitted while returning to source uid for destroying ccache
--

Expected results:
exit silently, remove the ccache.

Additional info:
Patch attached.