config: preserve scope in do_git_config_sequence

do_git_config_sequence operated under the assumption that it was correct
to set current_parsing_scope to CONFIG_SCOPE_UNKNOWN as part of the
cleanup it does after it finishes execution.  This is incorrect, as it
blows away the current_parsing_scope if do_git_config_sequence is called
recursively.  As such situations are rare (git config running with the
'--blob' option is one example) this has yet to cause a problem, but the
upcoming '--show-scope' option will experience issues in that case, lets
teach do_git_config_sequence to preserve the current_parsing_scope from
before it started execution.

Signed-off-by: Matthew Rogers <mattr94@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config.c

@@ -1702,6 +1702,7 @@ static int do_git_config_sequence(const struct config_options *opts,
 	char *xdg_config = xdg_config_home("config");
 	char *user_config = expand_user_path("~/.gitconfig", 0);
 	char *repo_config;
+	enum config_scope prev_parsing_scope = current_parsing_scope;
 
 	if (opts->commondir)
 		repo_config = mkpathdup("%s/config", opts->commondir);
@@ -1741,7 +1742,7 @@ static int do_git_config_sequence(const struct config_options *opts,
 	if (!opts->ignore_cmdline && git_config_from_parameters(fn, data) < 0)
 		die(_("unable to parse command-line config"));
 
-	current_parsing_scope = CONFIG_SCOPE_UNKNOWN;
+	current_parsing_scope = prev_parsing_scope;
 	free(xdg_config);
 	free(user_config);
 	free(repo_config);