Add .htaccess to sync exclude

ownCloud Server blacklists .htaccess files for security reasons - so it's useless to try to sync it.

See isBlacklisted() - https://github.com/owncloud/core/blob/fed34aecfa5b36c031ed754ed245549aa4a4194b/lib/filesystem.php#L388

sync-exclude.lst

@@ -27,4 +27,5 @@ Thumbs.db
 .fseventd
 .apdisk
 
+.htaccess