RESTCOMM-610 #Resolve-Issue Fixed

Conflicts:
	restcomm/restcomm.testsuite/src/test/java/org/mobicents/servlet/restcomm/ussd/UssdPullTest.java
	restcomm/restcomm.ussd/src/main/java/org/mobicents/servlet/restcomm/ussd/interpreter/UssdInterpreter.java
	restcomm/restcomm.ussd/src/main/java/org/mobicents/servlet/restcomm/ussd/telephony/UssdCall.java
	restcomm/restcomm.ussd/src/main/java/org/mobicents/servlet/restcomm/ussd/telephony/UssdCallManager.java