* gnome2.eclass: Pre-split clean-ups.

* gnome2.eclass: Pre-split clean-ups.

  Added a small comment header at the top.

  Prefix $SCROLLKEEPER_DIR with $ROOT and make sure it's used only in
  gnome2_scrollkeeper_update().

  (gnome2_src_configure): Clarify the comment for the addwrite call.

  (gnome2_src_install): Replace $SCROLLKEEPER_DIR with the local
  $sk_tmp_dir, since this function creates this dir under $D. Replace
  single debug-print call with specific mesages according to the method of
  installation used.

  (gnome2_gconf_install), (gnome2_gconf_uninstall): Added short comment.
  Return early if $GCONFTOOL_BIN is not valid. Declare F as local.

  (gnome2_icon_cache_update): Added short comment. Show output only if the
  function actually performs an update.

  (gnome2_omf_fix): Added comment about the function before its declaration.
  Removed redundant addition to $omf_makefiles.

  (gnome2_scrollkeeper_update): Added short comment.