Delete superfluous empty lines.

Delete superfluous empty lines.
(battery-linux-proc-acpi): Attempt to gather information from all
battery subdirectories regardless of their file name.
(battery-linux-proc-apm): Replace all occurrences of
battery-hex-to-int-2 with string-to-int (base 16).
(battery-hex-to-int-2, battery-hex-to-int): Delete functions.
(battery-hex-map): Delete variable.