source4 samr: Tidy DBG_WARNING calls

source4 samr: Tidy DBG_WARNING calls

Move the calls to GUID_buf_string and dom_sid_str_buf into the
coresponding DBG_WARNING call, instead of using an intermediate variable.
While this violates the coding guidelines, doing this makes the code less
cluttred and means the functions are only called if the debug message is
printed.

Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Wed Nov 21 01:50:11 CET 2018 on sn-devel-144