Infinite recursion possibility at Linux implementation

[svartalf]

Reference:

rust-battery/battery/src/platform/linux/sysfs/source.rs

Lines 175 to 183 in 34612e0

	fn energy_full_design(&self) -> Result<&Energy> {
	// Based on the `upower` source it seems to impossible not to have any of needed files,
	// so fallback to `0 mWh` was removed, error will be propagated instead.
	self.energy_full_design.try_borrow_with(|| {
	match fs::energy(self.root.join("energy_full_design")) {
	Ok(Some(value)) => Ok(value),
	Ok(None) => match fs::charge(self.root.join("charge_full_design")) {
	Ok(Some(value)) => Ok(value * *self.design_voltage()?),
	Ok(None) => Ok(*self.energy_full_design()?),

First of all, upower sources should be checked, since they were used as an knowledge source.
If nothing helpful can be borrowed from them, plain error should be returned there instead of calling the same one function.