pull up r19582 from trunk

pull up r19582 from trunk

 r19582@cathode-dark-space:  tlyu | 2007-06-18 17:07:37 -0400
 ticket: new
 subject: krb5_walk_realm_tree leaks in capaths case
 target_version: 1.6.2
 tags: pullup

 Markus Moeller reports a leak in krb5_get_credentials() which was then
 traced down to profile strings leaking from within
 krb5_walk_realm_tree().  A pointer to a profile string was getting
 overwritten without the string being freed when *cap_nodes[0] == '.'.
 Fix is to free the string prior to overwriting the pointer if the
 pointer is non-null.

ticket: 5579
version_fixed: 1.6.2

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-6@19593 dc483132-0cff-0310-8789-dd5450dbe970