Since the Fedora Live image runs GNOME Shell, which only has "Suspend" as discoverable shutdown option, it is very hard to find out how to restart or shutdown a Live session after having installed or tried out Fedora. As "Suspend" doesn't make much sense in a Live session anyway, it should be replaced by "Power Off..." (the status menu item which is visible when pressing Alt) in this case. (Note that I am only talking about Live sessions; in the installed Fedora, the item would be "Suspend" again.)
Seems like something that upstream should support. See: https://bugzilla.gnome.org/show_bug.cgi?id=659191
*** This bug has been marked as a duplicate of bug 705189 ***