Max-Forwards is actually optional.

See RFC 3261 section 16.3.3.

Bug: 3082615
Change-Id: I2435d03933e8c3494210bcf81b8b91d3c987e5d3
diff --git a/java/gov/nist/javax/sip/message/SIPRequest.java b/java/gov/nist/javax/sip/message/SIPRequest.java
index 3136383..25304c2 100644
--- a/java/gov/nist/javax/sip/message/SIPRequest.java
+++ b/java/gov/nist/javax/sip/message/SIPRequest.java
@@ -234,9 +234,13 @@
         if (getViaHeaders() == null) {
             throw new ParseException(prefix + ViaHeader.NAME, 0);
         }
+        // BEGIN android-deleted
+        /*
         if (getMaxForwards() == null) {
             throw new ParseException(prefix + MaxForwardsHeader.NAME, 0);
         }
+        */
+        // END android-deleted
 
         if (getTopmostVia() == null)
             throw new ParseException("No via header in request! ", 0);