Enabled concurrent requests while a stemcell is uploading

- Updated nginx to 1.4.5
- Added nginx module headers-more-v0.25
- Added nginx module nginx-upload-module-2.2
- Modified upload stemcell controller to use nginx's upload module,
  which handles uploading so that it doesn't block Ruby execution. This
  allows the director to respond to concurrent requests.

[#74421246]

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
Enabled concurrent requests while a release is uploading

[#74421246]

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
Enabled concurrent requests while a compiled package group is uploading

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
split up finder from a conditional

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
use nginx with integration tests and removed direct tgz upload to director ruby process

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
Do not truncate empty database

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
improve stemcell and release uploading integration tests
formatting blobstore nginx config
log response times in nginx log for director and blobstore

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>