[Tracker] Deprecate BatteryIndex option in favour of LowBatteryLimit

[Carlos Garnacho <carlos imendio com>]

Hi!,

tracker-hal now reports battery level, which tracker-indexer uses not to
keep indexing when the battery reaches critical limits, However this
somewhat conflicts with the BatteryIndex option, would it be ok to
replace it a LowBatteryLimit which works similarly to LowDiskLimit? It's
more flexible and useful IMHO

Regards,

-- 
Carlos Garnacho
Imendio AB - Expert solutions in GTK+
http://www.imendio.com