tool_operate: Don't use Windows CA store as a fallback

Background:

148534d added CURLSSLOPT_NATIVE_CA to use the Windows OS certificate
store in libcurl w/ OpenSSL on Windows. CURLSSLOPT_NATIVE_CA overrides
CURLOPT_CAINFO if both are set. The curl tool will fall back to
CURLSSLOPT_NATIVE_CA if it could not find a certificate bundle to set
via CURLOPT_CAINFO.

Problem:

libcurl may be built with hardcoded paths to a certificate bundle or
directory, and if CURLSSLOPT_NATIVE_CA is used then those paths are
ignored.

Solution:

A solution is still being discussed but since there's an impending
release this commit removes using CURLSSLOPT_NATIVE_CA in the curl tool.

Ref: https://github.com/curl/curl/issues/5585

src/tool_operate.c

@@ -2416,14 +2416,6 @@ static CURLcode transfer_per_config(struct GlobalConfig *global,
       else {
         result = FindWin32CACert(config, tls_backend_info->backend,
                                  "curl-ca-bundle.crt");
-#if defined(USE_WIN32_CRYPTO)
-        if(!config->cacert && !config->capath) {
-          /* user, and environment did not specify any ca file or path
-             and there is no "curl-ca-bundle.crt" file in standard path
-             so the only possible solution is using the windows ca store */
-          config->native_ca_store = TRUE;
-        }
-#endif
       }
 #endif
     }