Follow-up to r1717352, use apr version of snprintf

* buckets/request_buckets.c
  (serialize_data): use apr_snprintf
* buckets/response_buckets.c
  (serf_bucket_outgoing_response_prepare,
  serialize_outgoing_response): same


git-svn-id: https://svn.apache.org/repos/asf/serf/trunk@1717357 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/buckets/request_buckets.c b/buckets/request_buckets.c
index 7764ed1..50ef5e9 100644
--- a/buckets/request_buckets.c
+++ b/buckets/request_buckets.c
@@ -144,7 +144,7 @@
        use chunked encoding for the request.  */
     if (ctx->len != LENGTH_UNKNOWN) {
         char buf[30];
-        snprintf(buf, 30, "%" APR_INT64_T_FMT, ctx->len);
+        apr_snprintf(buf, 30, "%" APR_INT64_T_FMT, ctx->len);
         serf_bucket_headers_set(ctx->headers, "Content-Length", buf);
         if (ctx->body != NULL)
             serf_bucket_aggregate_append(bucket, ctx->body);
diff --git a/buckets/response_buckets.c b/buckets/response_buckets.c
index e0f63ac..0e3ee9b 100644
--- a/buckets/response_buckets.c
+++ b/buckets/response_buckets.c
@@ -852,7 +852,7 @@
        (assuming this method is called for HTTP2) */
     if (content_length != SERF_LENGTH_UNKNOWN) {
         char buf[30];
-        snprintf(buf, 30, "%" APR_INT64_T_FMT, content_length);
+        apr_snprintf(buf, 30, "%" APR_INT64_T_FMT, content_length);
 
         serf_bucket_headers_setc(ctx->headers, "Content-Length", buf);
     }
@@ -884,7 +884,7 @@
         char start[32];
         struct iovec status_vecs[3];
 
-        snprintf(start, 32, "HTTP/%d.%d %03d ",
+        apr_snprintf(start, 32, "HTTP/%d.%d %03d ",
                 SERF_HTTP_VERSION_MAJOR(ctx->http_version),
                 SERF_HTTP_VERSION_MINOR(ctx->http_version),
                 ctx->status);