Fix a couple problems with DownloadItemGtk.
Fix a couple problems with DownloadItemGtk.

1) We were crashing after removing a download item because g_signal_handler_find() was not working as expected.
2) We had a graphical glitch with the dangerous download dialog because GtkAlignments doesn't normally redraw on allocate.

BUG=13659
Review URL: http://codereview.chromium.org/118403

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@18132 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser