Merge of r4405:

Fixed division by zero exception in ngx_hash_init().

The ngx_hash_init() function did not expect call with zero elements count,
which caused FPE error on configs with an empty "types" block in http context
and "types_hash_max_size" > 10000.

src/core/ngx_hash.c

diff --git a/src/core/ngx_hash.c b/src/core/ngx_hash.c
index 0c72852..74d89b8 100644
--- a/src/core/ngx_hash.c
+++ b/src/core/ngx_hash.c
@@ -277,7 +277,7 @@
     start = nelts / (bucket_size / (2 * sizeof(void *)));
     start = start ? start : 1;
 
-    if (hinit->max_size > 10000 && hinit->max_size / nelts < 100) {
+    if (hinit->max_size > 10000 && nelts && hinit->max_size / nelts < 100) {
         start = hinit->max_size - 1000;
     }