use CURLcode, not int, prevents picky compilers to warn

lib/content_encoding.c

@@ -74,7 +74,7 @@ Curl_unencode_deflate_write(struct SessionHandle *data,
                             ssize_t nread)
 {
   int status;                   /* zlib status */
-  int result = CURLE_OK; /*?*/  /* Curl_client_write status */
+  CURLcode result = CURLE_OK; /*?*/  /* Curl_client_write status */
   char decomp[DSIZ];            /* Put the decompressed data here. */
   z_stream *z = &k->z;          /* zlib state structure */