Reserve room for 16 response headers by default.
Review Request #121408 - Created Dec. 9, 2014 and submitted
|dvratil, mlaurent, vkrause|
In my data, most often the final size of fetchResponse is 16. By reserving that data upfront, we can get rid of 3/4 of the list allocations, according to the growth-strategy outlined here: http://qt-project.org/doc/qt-4.8/containers.html#growth-strategies I.e. before, we'd allocate 4, 8, 12, 16. Now we directly allocate room for 16.