Fix b/27579535: Override the default getDocContent response timeouts.
Fix b/27579535: Override the default getDocContent response timeouts.

This change increases the response timeouts to tolerate crawling
larger files and directories and/or slower file systems.  The
default response header timeout was 30 seconds, and the default
content timeout was 3 minutes.  This change sets both timeouts
at 10 minutes.

The large header timeout is to accomodate listing large directories,
which supply most of the directory entries as X-Gsa-External-Anchor
header fields.  A customer was timing out listing directories with
100,000 entries.  Generating a getDocContent response with 100,000
external anchors took approximately 5 1/2 minutes on my machine,
so a 10 minute timeout should accomodate all but the most extreme
scenerios.

Code Review: http://codereview.appspot.com/288570043

googlegsa/filesystem,googlegsa/filesystem,googlegsa/filesystem