After-review cleanup of Bug#57428: replace the dulint struct with a 64-bit int

trx_undo_build_roll_ptr(): Clarify the assertion on is_insert being 0 or 1.

TRX_SYS_FILE_FORMAT_TAG: Remove "extra" space after period in the comment.
See also http://desktoppub.about.com/cs/typespacing/a/onetwospaces.htm

storage/innobase/include/trx0undo.ic

@@ -43,7 +43,7 @@ trx_undo_build_roll_ptr(
 #if DATA_ROLL_PTR_LEN != 7
 # error "DATA_ROLL_PTR_LEN != 7"
 #endif
-	ut_ad(is_insert <= 1);
+	ut_ad(is_insert == 0 || is_insert == 1);
 	ut_ad(rseg_id < TRX_SYS_N_RSEGS);
 	ut_ad(offset < 65536);