SPDY: constant number of preallocated structures for headers.

src/http/ngx_http_spdy.c

diff --git a/src/http/ngx_http_spdy.c b/src/http/ngx_http_spdy.c
index b5bfe18..2b7b89f 100644
--- a/src/http/ngx_http_spdy.c
+++ b/src/http/ngx_http_spdy.c
@@ -1038,7 +1038,7 @@
                        "spdy HEADERS block consists of %ui entries",
                        sc->entries);
 
-        if (ngx_list_init(&r->headers_in.headers, r->pool, sc->entries + 3,
+        if (ngx_list_init(&r->headers_in.headers, r->pool, 20,
                           sizeof(ngx_table_elt_t))
             != NGX_OK)
         {