Increase the max number of buffers in ByteBufferPool

Before the HBASE-15525 issue fix, we had variable sized buffers in our buffer pool. The max size upto which one buffer can grow was 2 MB. Now we have changed it to be a fixed sized BBPool. By default 64 KB is the size of each buffer. But the max number of BBs allowed to be in the pool was not changed. ie. twice the number of handlers. May be we should be changing increasing it now? To make it equal to the way like 2 MB, we will need 32 * 2 * handlers. There is no initial #BBs any way. 2 MB is the default max response size what we have. And write reqs also, when it is Buffered mutator 2 MB is the default flush limit. We can make it to be 32 * #handlers as the def max #BBs I believe.