added an icon to the progress dialog

Based on FR commit: f6fa4bdb5ccc059a6b13938e6b017bcefed2c8ab
From: Paolo Bacchilega <paobac@src.gnome.org>
do not call release_data if the data was not initialized

Based on FR commit: 05c0b2c366f5524645167d9dca2268219563559d
From: Paolo Bacchilega <paobac@src.gnome.org>
configure.ac: removed unneeded parenthesis