Run in Ubuntu 32 bits

This is an umbrella issue to solve the problems preventing us from running the riak_test suite on the Ubuntu 10 32 bits platform.  The current plan is to patch LevelDB to use 32 bit performance counters on 32 bit platforms + allowing riak_test to be configured to use less resources since LevelDB allocates a lot of memory per vnode at startup. Also, LevelDB is used by AAE, so that may need tweaks too to avoid hitting the 32 bit memory limit on the tests.