Merge branch 'jc/apply-reject-noop-hunk'

"git apply" cannot diagnose a patch corruption when the breakage is
to mark the length of the hunk shorter than it really is on the
hunk header line "@@ -l,k +m,n @@"; one special case it could is
when the hunk becomes no-op (e.g. k == n == 2 for two-line context
patch output), and it learned how to do so.

* jc/apply-reject-noop-hunk:
  apply: reject a hunk that does not do anything

builtin/apply.c

@@ -1638,6 +1638,9 @@ static int parse_fragment(const char *line, unsigned long size,
 	}
 	if (oldlines || newlines)
 		return -1;
+	if (!deleted && !added)
+		return -1;
+
 	fragment->leading = leading;
 	fragment->trailing = trailing;