PROTON-611: Don't allocate frame_max bytes immediately, grow by factors of 2 until
you get to the max - else a large frame size can blow away 4Gb of memory!

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1617376 13f79535-47bb-0310-9956-ffa450edef68