HTTP/2: fixed debug log about indexed headers.
HTTP/2: fixed debug log about indexed headers.

Previously, "get indexed header" message was logged when in fact only
header name was obtained using an index, and "get indexed header name"
was logged when full header representation (name and value) was obtained
using an index.  Fixed version logs "get indexed name" and "get indexed
header" respectively.

hy0kl/nginx,hy0kl/nginx,hy0kl/nginx