CLEANUP: http: Remove unused HTTP message templates

HTTP_1XX, HTTP_3XX and HTTP_4XX message templates are no longer used. Only
HTTP_302 and HTTP_303 are used during configuration parsing by "errorloc" family
directives. So these templates are removed from the generic http code. And
HTTP_302 and HTTP_303 templates are moved as static strings in the function
parsing "errorloc" directives.
diff --git a/src/http_htx.c b/src/http_htx.c
index 3137fbe..7211a4d 100644
--- a/src/http_htx.c
+++ b/src/http_htx.c
@@ -1223,6 +1223,17 @@
  */
 struct buffer *http_parse_errorloc(int errloc, int status, const char *url, char **errmsg)
 {
+	static const char *HTTP_302 =
+		"HTTP/1.1 302 Found\r\n"
+		"Cache-Control: no-cache\r\n"
+		"Content-length: 0\r\n"
+		"Location: "; /* not terminated since it will be concatenated with the URL */
+	static const char *HTTP_303 =
+		"HTTP/1.1 303 See Other\r\n"
+		"Cache-Control: no-cache\r\n"
+		"Content-length: 0\r\n"
+		"Location: "; /* not terminated since it will be concatenated with the URL */
+
 	struct buffer *buf = NULL;
 	const char *msg;
 	char *key = NULL, *err = NULL;