Sieve file storage: Fixed couple of Coverity warnings.

src/lib-sieve/storage/file/sieve-file-script.c

@@ -354,13 +354,7 @@ static int sieve_file_script_open
 			if ( ret < 0 ) {
 				/* Make sure we have a script name for the error */
 				if ( name == NULL ) {
-					if ( basename == NULL ) {
-						if ( filename == NULL )
-							filename = path_split_filename(path, &dirpath);
-						basename = sieve_script_file_get_scriptname(filename);
-						if ( basename == NULL )
-							basename = filename;
-					}
+					i_assert( basename != NULL );
 					name = basename;
 				}
 				sieve_file_script_handle_error

src/lib-sieve/storage/file/sieve-file-storage.c

@@ -298,6 +298,8 @@ static int sieve_file_storage_init_common
 	bool have_link = FALSE;
 	int ret;
 
+	i_assert( storage_path != NULL || active_path != NULL );
+
 	fstorage->prev_mtime = (time_t)-1;
 
 	/* Get active script path */