Dialog class: Using button "Close" instead of "Reset"

Previously Dialog didn't offer "Close" button to quit
that dialog, also "Reset" button was unnecessary.
Now using button "Close" instead of "Reset".

Change-Id: Ifea2929a328da50493f5336d389b07202ac755b1
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=977267
Signed-off-by: hadong <hadong0720@gmail.com>