Replace more speedbar uses of end-of-line etc with line-end-position.

Replace more speedbar uses of end-of-line etc with line-end-position.
* lisp/speedbar.el (speedbar-generic-item-info)
(speedbar-item-info-tag-helper, speedbar-change-expand-button-char)
(speedbar-add-indicator, speedbar-check-vc-this-line)
(speedbar-check-obj-this-line, speedbar-extract-one-symbol)
(speedbar-buffers-line-directory, speedbar-buffer-revert-buffer):
Replace more uses of end-of-line etc with line-end-position.