Minor _lp_battery correction, defaults

- Remove the end of line (after the '%' character) before removing the
  beggining of line from the output of acpi.

  When (dis)charging, `acpi --battery` would output something like
      "Battery 0: Discharging, 63%, 02:51:50 remaining"
  The removal of the beggining of line would stop at the last comma
  instead of stopping at the first one and would output
      "02:51:50 remaining"
  instead of
      "63%, 02:51:50 remaining"

- Set the right values to some global variables.