nsswitch: Fix memory leak in wbinfo_auth_krb5()

nsswitch: Fix memory leak in wbinfo_auth_krb5()

Direct leak of 48 byte(s) in 1 object(s) allocated from:
    #0 0x7ff206afc130 in calloc ../../../../libsanitizer/asan/asan_malloc_linux.cpp:77
    #1 0x7ff206837054 in wbcAllocateMemory ../../nsswitch/libwbclient/wbclient.c:216
    #2 0x7ff20683c76a in wbc_create_password_policy_info ../../nsswitch/libwbclient/wbc_pam.c:295
    #3 0x7ff20683c76a in wbcCtxLogonUser ../../nsswitch/libwbclient/wbc_pam.c:1290
    #4 0x7ff20683caec in wbcLogonUser ../../nsswitch/libwbclient/wbc_pam.c:1307
    #5 0x556ea348db12 in wbinfo_auth_krb5 ../../nsswitch/wbinfo.c:1723
    #6 0x556ea348db12 in main ../../nsswitch/wbinfo.c:3238
    #7 0x7ff203c2a2ad in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Martin Schwenke <martin@meltin.net>