sipcall: Modify calls handling process

Integration of new security features implies modifications in call handling.
By default, when handling a call,  a SipCall object is created, but if ZRTP hooks
are activated, the call is dynamically subclassed, and becomes a SecureSipCall.

Refs #40939
diff --git a/src/org/sflphone/model/BubbleContact.java b/src/org/sflphone/model/BubbleContact.java
index 8e2f0d3..3ad500d 100644
--- a/src/org/sflphone/model/BubbleContact.java
+++ b/src/org/sflphone/model/BubbleContact.java
@@ -57,7 +57,7 @@
     }
 
     public BubbleContact(Context context, SipCall call, float x, float y, float size) {
-        super(context, call.getContact(), x, y, size);
+        super(context, call.getmContact(), x, y, size);
         associated_call = call;
 
         buttonMsg = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.ic_action_chat);
@@ -379,7 +379,7 @@
 
     @Override
     public String getName() {
-        return associated_call.getContact().getmDisplayName();
+        return associated_call.getmContact().getmDisplayName();
     }
 
     @Override