tools/kvm_stat: cut down decimal places in update interval dialog

We currently display the default number of decimal places for floats in
_show_set_update_interval(), which is quite pointless. Cutting down to a
single decimal place.
Signed-off-by: NStefan Raspl <raspl@linux.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

tools/kvm/kvm_stat/kvm_stat

@@ -1325,7 +1325,7 @@ class Tui(object):
         msg = ''
         while True:
             self.screen.erase()
-            self.screen.addstr(0, 0, 'Set update interval (defaults to %fs).' %
+            self.screen.addstr(0, 0, 'Set update interval (defaults to %.1fs).' %
                                DELAY_DEFAULT, curses.A_BOLD)
             self.screen.addstr(4, 0, msg)
             self.screen.addstr(2, 0, 'Change delay from %.1fs to ' %