apt.systemd.daily: Put opening brace of check_power on extra line

The rest is also on the same line, so let's go consistent here
now that we have a bug report about it.

LP: #1581985

debian/apt.systemd.daily

@@ -290,7 +290,8 @@ debug_echo()
     fi
 }
 
-check_power(){
+check_power()
+{
     # laptop check, on_ac_power returns:
     #       0 (true)    System is on main power
     #       1 (false)   System is not on main power