Support for using SSSD (http://fedorahosted.org/sssd/) as a sudoers

data source.  From Daniel Kopecek and Pavel Brezina.

include/sudo_debug.h

@@ -71,6 +71,7 @@
 #define SUDO_DEBUG_PERMS	(23<<6)	/* uid/gid swapping functions */
 #define SUDO_DEBUG_PLUGIN	(24<<6)	/* main plugin functions */
 #define SUDO_DEBUG_HOOKS	(25<<6)	/* hook functions */
+#define SUDO_DEBUG_SSSD		(26<<6) /* sudoers SSSD */
 #define SUDO_DEBUG_ALL		0xfff0	/* all subsystems */
 
 /* Flag to include string version of errno in debug info. */