diff --check: fix off by one error

When parsing the diff line starting with '@@', the line number of the
'+' file is parsed. For the subsequent line parses, the line number
should therefore be incremented after the parse, not before it.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/diff.c b/diff.c
index 3315378..b003c000 100644
--- a/diff.c
+++ b/diff.c
@@ -825,8 +825,6 @@
 	if (line[0] == '+') {
 		int i, spaces = 0;
 
-		data->lineno++;
-
 		/* check space before tab */
 		for (i = 1; i < len && (line[i] == ' ' || line[i] == '\t'); i++)
 			if (line[i] == ' ')
@@ -841,6 +839,8 @@
 		if (isspace(line[len - 1]))
 			printf("%s:%d: white space at end: %.*s\n",
 				data->filename, data->lineno, (int)len, line);
+
+		data->lineno++;
 	} else if (line[0] == ' ')
 		data->lineno++;
 	else if (line[0] == '@') {