libfreerdp/utils/http.c: fix resource leak

found by coverity

128                if (winpr_asprintf(&headers, &size, post_header_fmt, path, hostname, blen) < 0)

CID 424888: (#1 of 1): Resource leak (RESOURCE_LEAK)
15. leaked_storage: Variable hostname going out of scope leaks the storage it points to.
129                        return FALSE;
130        }

libfreerdp/utils/http.c

@@ -126,12 +126,18 @@ BOOL freerdp_http_request(const char* url, const char* body, long* status_code,
 	{
 		blen = strlen(body);
 		if (winpr_asprintf(&headers, &size, post_header_fmt, path, hostname, blen) < 0)
+		{
+			free(hostname);
 			return FALSE;
+		}
 	}
 	else
 	{
 		if (winpr_asprintf(&headers, &size, get_header_fmt, path, hostname) < 0)
+		{
+			free(hostname);
 			return FALSE;
+		}
 	}
 
 	ssl_ctx = SSL_CTX_new(TLS_client_method());