FIX FOR : http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6494397
[ JCA Connection pool should try to evict some free connections if a new connection 
cannot fit in pool ]

When multiple user credentials are used to get connection, connection pool must
serve the requests as long as there are free connections in the pool.

eg scenario:
max-pool-size : 32
steady-pool-size : 8
pool-resize-quantity : 2
match-connections : true

3 user credentials.

First user acquires 16 connections.
Second user acquires 16 connections.
All connections are returned to pool.
Currently the pool has 32 connections but only with 2 user credentials.

Request to third user must succeed as there are free connections
(even though the credentials does not match) by
purging unmatched free connections and provide new connections.