SPDY: fixed one case of improper memory allocation error handling.

Now ngx_http_spdy_construct_request_line() doesn't try to finalize request
in case of failed memory allocation.

src/http/ngx_http_spdy.c

diff --git a/src/http/ngx_http_spdy.c b/src/http/ngx_http_spdy.c
index a09e4ac..059adc9 100644
--- a/src/http/ngx_http_spdy.c
+++ b/src/http/ngx_http_spdy.c
@@ -2900,7 +2900,8 @@
 
     p = ngx_pnalloc(r->pool, r->request_line.len + 1);
     if (p == NULL) {
-        ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
+        ngx_http_spdy_close_stream(r->spdy_stream,
+                                   NGX_HTTP_INTERNAL_SERVER_ERROR);
         return NGX_ERROR;
     }