Fixed incorrect ngx_str_set() usage, broken in c82b2e020b9f.

Found by Coverity Scan CID 1135525.

Signed-off-by: Piotr Sikora <piotr@cloudflare.com>

src/http/modules/ngx_http_uwsgi_module.c

diff --git a/src/http/modules/ngx_http_uwsgi_module.c b/src/http/modules/ngx_http_uwsgi_module.c
index a0a7715..0cfaede 100644
--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -603,7 +603,7 @@
         url.url.len -= add;
 
     } else {
-        ngx_str_set(&u->schema, (u_char *) "uwsgi://");
+        ngx_str_set(&u->schema, "uwsgi://");
     }
 
     url.no_resolve = 1;