Lights Wrapper: reset use_pattern and pattern_data on notif LED turning off

This will solve the conflict between previous pattern settings and Battery LED.
Without this patch, the LED may misbehave when battery LED state
and notif LED state both change. E.G. when battery percentage reached
15% from 14% and IM messages arrived at the same time, the LED may show
yellow then green, and yellow again. Normally it should be
green blinking (for IM Message), and after you viewed the messages,
it should be yellow (for charging battery over 15%).
(And some misspelling fix)

PS2: removed unnecessary declaration
PS3: fix a mistake when clearing pattern_data

Change-Id: I497a86f3ede33032cbd2fb1a517326d4cd088437