config: close config file handle in case of error

When updating an existing configuration file, we did not always
close the filehandle that is reading from the current configuration
file when we encountered an error (e.g. when unsetting a variable
that does not exist).

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config.c

@@ -1935,7 +1935,7 @@ int git_config_set_multivar_in_file(const char *config_filename,
 				const char *key, const char *value,
 				const char *value_regex, int multi_replace)
 {
-	int fd = -1, in_fd;
+	int fd = -1, in_fd = -1;
 	int ret;
 	struct lock_file *lock = NULL;
 	char *filename_buf = NULL;
@@ -2065,6 +2065,7 @@ int git_config_set_multivar_in_file(const char *config_filename,
 			goto out_free;
 		}
 		close(in_fd);
+		in_fd = -1;
 
 		if (chmod(lock->filename.buf, st.st_mode & 07777) < 0) {
 			error("chmod on %s failed: %s",
@@ -2148,6 +2149,8 @@ int git_config_set_multivar_in_file(const char *config_filename,
 	free(filename_buf);
 	if (contents)
 		munmap(contents, contents_sz);
+	if (in_fd >= 0)
+		close(in_fd);
 	return ret;
 
 write_err_out: