Add cgit_free_commitinfo() and use where needed

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
diff --git a/ui-log.c b/ui-log.c
index c52af79..b7da49f 100644
--- a/ui-log.c
+++ b/ui-log.c
@@ -28,10 +28,7 @@
 	html("</td><td>");
 	html_txt(info->author);
 	html("</td></tr>\n");
-	free(info->author);
-	free(info->committer);
-	free(info->subject);
-	free(info);
+	cgit_free_commitinfo(info);
 }