org-odt.el: Fix byte-compiler warnings.

org-odt.el: Fix byte-compiler warnings.

* lisp/org-odt.el:
(org-odt-end-table): Bind r, c and spec
(org-odt-fill-tabs-and-spaces): Use org-odt-format-tabs.
(org-odt-get-image-name): Use the correct param
(org-parse-table-of-contents, org-table-begin-marker)
(org-table-rowgroup-open, org-table-rownum)
(org-table-current-rowgroup-is-header, org-table-is-styled)
(org-table-rowgroup-info, org-table-colalign-vector)
(org-parse-link-description-is-image, org-table-ncols ):
defvar these to suppress byte-compiler warnings.
(org-odt-format-tag):  Removed. Stray function
(org-table-row-styles-plist): Removed. Stray variable.