IMS: Add phoneaccount to ims conference call.

Retrieve phoneaccount from ParcelableConference coming from
TeleService and set that account to Telecom Conference call.
This prevents hold and dial request from getting invoked from
Telecom during adding a call on top of an existing ims 3 way
conference call.

Bug: 18690773

Change-Id: Ie02e12c77272c2c889b1c7377e0bf461e67a1abd
diff --git a/src/com/android/server/telecom/ConnectionServiceWrapper.java b/src/com/android/server/telecom/ConnectionServiceWrapper.java
index d06dded..533b715 100644
--- a/src/com/android/server/telecom/ConnectionServiceWrapper.java
+++ b/src/com/android/server/telecom/ConnectionServiceWrapper.java
@@ -243,7 +243,8 @@
 
                         // need to create a new Call
                         PhoneAccountHandle phAcc = null;
-                        if (parcelableConference != null) {
+                        if (parcelableConference != null &&
+                                parcelableConference.getPhoneAccount() != null) {
                             phAcc = parcelableConference.getPhoneAccount();
                         }
                         Call conferenceCall = mCallsManager.createConferenceCall(