ignore: remove now-useless check for LEADINGDIR

When checking whether a rule negates another rule, we were checking
whether a rule had the `GIT_ATTR_FNMATCH_LEADINGDIR` flag set and, if
so, added a "/*" to its end before passing it to `fnmatch`. Our code now
sets `GIT_ATTR_FNMATCH_NOLEADINGDIR`, thus the `LEADINGDIR` flag shall
never be set. Furthermore, due to the `NOLEADINGDIR` flag, trailing
globs do not get consumed by our ignore parser anymore.

Clean up code by just dropping this now useless logic.

src/ignore.c

@@ -133,23 +133,12 @@ static int does_negate_rule(int *out, git_vector *rules, git_attr_fnmatch *match
 				continue;
 		}
 
-		/*
-		 * When dealing with a directory, we add '/<star>' so
-		 * p_fnmatch() honours FNM_PATHNAME. Checking for LEADINGDIR
-		 * alone isn't enough as that's also set for nagations, so we
-		 * need to check that NEGATIVE is off.
-		 */
 		git_buf_clear(&buf);
-		if (rule->containing_dir) {
+		if (rule->containing_dir)
 			git_buf_puts(&buf, rule->containing_dir);
-		}
-
-		error = git_buf_puts(&buf, rule->pattern);
+		git_buf_puts(&buf, rule->pattern);
 
-		if ((rule->flags & (GIT_ATTR_FNMATCH_LEADINGDIR | GIT_ATTR_FNMATCH_NEGATIVE)) == GIT_ATTR_FNMATCH_LEADINGDIR)
-			error = git_buf_PUTS(&buf, "/*");
-
-		if (error < 0)
+		if (git_buf_oom(&buf))
 			goto out;
 
 		if ((error = p_fnmatch(git_buf_cstr(&buf), path, fnflags)) < 0) {