impress: fixed incorrect slide pasting position

problem:
when context menu was invoked by clicking on the empty
spaces in the slidesorter, and slides were pasted using
option in the context menu, slides were always pasted
at the end and not where it was clicked

Signed-off-by: Pranam Lashkari <lpranam@collabora.com>
Change-Id: I2aba5d37ffca1eb86b02d76563887eae71ace2e6

Author: lpranam

browser/src/control/Control.PartsPreview.js

@@ -268,12 +268,9 @@ window.L.Control.PartsPreview = window.L.Control.extend({
 					paste: {
 						name: app.IconUtil.createMenuItemLink(_('Paste Slide'), 'Paste'),
 						isHtmlName: true,
-						callback: function(key, options) {
-							var part = that._findClickedPart(options.$trigger[0].parentNode);
-							if (part !== null) {
+						callback: function() {
 								that._setPart(that.copiedSlide);
-								that._map.duplicatePage(parseInt(part));
-							}
+								that._map.duplicatePage(parseInt(nPos));
 						},
 						visible: function() {
 							return that.copiedSlide;