auth: Fix handling passdbs with identical driver/args but different
mechanisms/username_filter
7bad6a24160e34bce8f10e73dbbf9e5fbbcd1904

Index: src/auth/passdb.h
--- src/auth/passdb.h.orig
+++ src/auth/passdb.h
@@ -63,10 +63,6 @@ struct passdb_module {
 	/* Default password scheme for this module.
 	   If default_cache_key is set, must not be NULL. */
 	const char *default_pass_scheme;
-	/* Supported authentication mechanisms, NULL is all, [NULL] is none*/
-	const char *const *mechanisms;
-	/* Username filter, NULL is no filter */
-	const char *const *username_filter;
 
 	/* If blocking is set to TRUE, use child processes to access
 	   this passdb. */