KAM26-27 remove headers and record_route on internal redirect

* record_route and consume_credentials are not preserved as well as removal of headers like Route
  we need to "redo" those on internal redirect.
  a config option KZ_INTERNAL_REDIRECT_RESERVED_HEADERS was made to set which headers ishould be removed.
  it can be set at runtime with kamcmd cfg.set kazoo internal_redirect_reserved_headers <regex expression>

(cherry picked from commit ebb31d5)

kamailio/default.cfg

@@ -912,6 +912,8 @@ failure_route[INTERNAL_FAULT]
 route[INTERNAL_REDIRECT]
 {
     xlog("L_INFO", "redirect to $T_rpl($hdr(X-Redirect-Server))\n");
+    remove_hf_re_pv("$sel(cfg_get.kazoo.internal_redirect_reserved_headers)");
+    record_route();
 
     if (ds_is_from_list(-1, 7, "$T_rpl($hdr(X-Redirect-Server))")) {
         xlog("L_INFO", "found dispatcher redirect for $T_rpl($hdr(X-Redirect-Server)) => $var(ds_uri)\n");

kamailio/defs.cfg

@@ -26,6 +26,7 @@
 #!trydef OVERRIDE_MEDIA_REPLY_480 603
 
 #!trydef KZ_RESERVED_HEADERS "^(X-AUTH|X-KAZOO|X-FS-|Referred-By)"
+#!trydef KZ_INTERNAL_REDIRECT_RESERVED_HEADERS "^(Route|Proxy-Authorization)"
 
 
 kazoo.to_internal_no_response_timer = EXTERNAL_TO_INTERNAL_NO_RESPONSE_TIMER descr "external to internal no response timer"
@@ -43,6 +44,7 @@ kazoo.to_external_no_response_18X_timer = INTERNAL_TO_EXTERNAL_NO_RESPONSE_18X_T
 kazoo.override_media_reply_480 = OVERRIDE_MEDIA_REPLY_480 descr "sip code to send upstream when media returns 480 with session in progress"
 
 kazoo.reserved_headers = KZ_RESERVED_HEADERS descr "headers that are removed"
+kazoo.internal_redirect_reserved_headers = KZ_INTERNAL_REDIRECT_RESERVED_HEADERS descr "headers that are removed on internal redirect"
 
 #!ifndef MY_HOSTNAME
 #!substdef "!MY_HOSTNAME!$HN(f)!g"