rest_client: Fix a rest_post() regression bug

Commit c549e6e added an unnecessary libcurl option which caused
the HTTP headers to be logged into the output body pseudo-variable
alongside the request body when performing a rest_post().

This patch disables the above-mentioned libcurl option (CURLOPT_HEADER).

Reported by @goharahmed on GitHub.
Fixes #1247.

(cherry picked from commit 91d7e7f)

modules/rest_client/rest_methods.c

@@ -847,12 +847,9 @@ int rest_post_method(struct sip_msg *msg, char *url, char *body, char *ctype,
 	w_curl_easy_setopt(sync_handle, CURLOPT_STDERR, stdout);
 	w_curl_easy_setopt(sync_handle, CURLOPT_FAILONERROR, 0);
 
-	w_curl_easy_setopt(sync_handle, CURLOPT_HEADER, 1L);
 	w_curl_easy_setopt(sync_handle, CURLOPT_WRITEFUNCTION, write_func);
 	w_curl_easy_setopt(sync_handle, CURLOPT_WRITEDATA, &res_body);
 
-
-
 	w_curl_easy_setopt(sync_handle, CURLOPT_HEADERFUNCTION, header_func);
 	w_curl_easy_setopt(sync_handle, CURLOPT_HEADERDATA, &st);