CURLINFO_SCHEME.3: fix variable type

.SH SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_SCHEME, long *p);

CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_SCHEME, char **scheme);

.SH DESCRIPTION

Pass a pointer to a char pointer to receive the pointer to a zero-terminated

string holding the URL scheme used for the most recent connection done with this

\fBcurl\fP handle.

string holding the URL scheme used for the most recent connection done with

this CURL \fBhandle\fP.

The \fBid\fP pointer will be NULL or pointing to private read-only memory you

MUST NOT free or modify.

The \fBscheme\fP pointer will be NULL or pointing to private memory you MUST

NOT free - it gets freed when you call \fIcurl_easy_cleanup(3)\fP on the

corresponding CURL handle.

.SH PROTOCOLS

All

.SH EXAMPLE

  curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");

  res = curl_easy_perform(curl);

  if(res == CURLE_OK) {

    char * scheme;

    char *scheme = NULL;

    curl_easy_getinfo(curl, CURLINFO_SCHEME, &scheme);

    if(scheme)

      printf("scheme: %s\\n", scheme); /* scheme: HTTP */

  }

  curl_easy_cleanup(curl);

}