Fix the maddr issue for proxy authentication.

bug:4185114
Change-Id: I7832ffaa4383a84970293bcb921e3fb1fa1ccec4
diff --git a/java/gov/nist/javax/sip/clientauthutils/AuthenticationHelperImpl.java b/java/gov/nist/javax/sip/clientauthutils/AuthenticationHelperImpl.java
index aa29616..4dc39ef 100644
--- a/java/gov/nist/javax/sip/clientauthutils/AuthenticationHelperImpl.java
+++ b/java/gov/nist/javax/sip/clientauthutils/AuthenticationHelperImpl.java
@@ -212,7 +212,8 @@
                 Hop hop   = ((SIPClientTransaction) challengedTransaction).getNextHop();
                 SipURI sipUri = (SipURI) reoriginatedRequest.getRequestURI();
                 // BEGIN android-added
-                if ( !hop.getHost().equalsIgnoreCase(sipUri.getHost()) )
+                if ( !hop.getHost().equalsIgnoreCase(sipUri.getHost())
+                        && !hop.equals(sipStack.getRouter(challengedRequest).getOutboundProxy()) )
                 // END android-added
                 sipUri.setMAddrParam(hop.getHost());
                 if ( hop.getPort() != -1 ) sipUri.setPort(hop.getPort());