xbps-repo: changed the 'sync' target to update from all registered

remote repositories, so remove its argument.

xbps_sync_repository_pkg_index:
 - create the local repo dir in XBPS_META_PATH.
 - also add the uri scheme (http://, https://, ftp://) in the created
   local directory and subst ':' also with an underscore.
 - do not create local repo directories unless the download pkg-index
   plist file is verified to be fetched correctly.

xbps_check_is_repo_string_remote:
  New function to check if a repo string is a remote repository, use
  it in all places where it was used before.

--HG--
extra : convert_revision : xtraeme%40gmail.com-20091123042316-rmu4w3ehoxwh3iz8

bin/xbps-bin/install.c

@@ -122,8 +122,7 @@ download_package_list(prop_object_iterator_t iter)
 		/*
 		 * Skip packages in local repositories.
 		 */
-		if ((strncmp(repoloc, "http://", 7)) &&
-		    (strncmp(repoloc, "ftp://", 6)))
+		if (!xbps_check_is_repo_string_remote(repoloc))
 			continue;
 
 		prop_dictionary_get_cstring_nocopy(obj, "pkgver", &pkgver);