bugfix: ngx_http_upstream_init_process will cause coredump while not have http block.
Feature: the "gzip_clear_etag" directive.
Merge pull request #515 from taoyuanyuan/random

bugfix: ngx_http_upstream_init_process will cause coredump
Merge pull request #514 from taoyuanyuan/etag

Feature: the "gzip_clear_etag" directive.
add doc for the "gzip_clear_etag" directive.
Merge pull request #516 from taoyuanyuan/doc

add doc for the "gzip_clear_etag" directive.