Add keepalive_requests and client_body_buffer_size options

[bai]

This PR adds two extra nginx config options: keepalive_requests and client_body_buffer_size.

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[k8s-reviewable]

This change is 

[bai]

CLA signed.

[coveralls]

Coverage increased (+0.05%) to 46.955% when pulling 3bd2cb3 on bai:keepalice-and-body-buffer-config into 8ca5fbe on kubernetes:master.

[coveralls]

Coverage increased (+0.05%) to 46.955% when pulling 3bd2cb3 on bai:keepalice-and-body-buffer-config into 8ca5fbe on kubernetes:master.

[aledbf]

/lgtm

[aledbf]

@bai thanks!

[aledbf]

@bai thanks!