use URI with query args for HA2

Otherwise, it will apparently not work at all for URLs with query args.
Tested with nginx 1.0.14.
Use ngx_snprintf to take url part from unparsed_uri.data.
We need this because unparsed_uri.data does not ends with '\0' after url part.
Merge pull request #1 from hnakamur/use_unparsed_uri_substr

Use ngx_snprintf to take url part from unparsed_uri.data.
Do not add the timer if nginx is exiting
remove unsed variable.
omit the access check only when the internal request