Make Apache HttpClient play nice with large kernel socket buffers.

Given the large maximum size likely to be set for kernel socket buffers on LTE
devices, we need to stop Apache HttpClient from allocating some integer
multiple of that size on the heap for each socket. On one device, 16 HTTP
connections would fill the heap.

Bug: 3514259
Change-Id: I888c03b6ad4b7ca444c2c423b097a3f76390846b