https://issues.apache.org/jira/browse/AMQCPP-601

Fixes for priority backup handling to prevent stall when reconnecting
tries to use a priority instance.
(cherry picked from commit a8ff8b54e0d75fb751f5b76682c715a78ee8150d)

# Conflicts:
#	activemq-cpp/src/main/activemq/transport/failover/FailoverTransport.cpp
#	activemq-cpp/src/test/activemq/transport/failover/FailoverTransportTest.cpp
#	activemq-cpp/src/test/activemq/transport/failover/FailoverTransportTest.h
#	activemq-cpp/src/test/testRegistry.cpp
8 files changed