Move lockscreen buttons options to one place

When you enter "Button actions" you expect to find unlock
options there, not in "Screen security -> Additional options".
Before: http://goo.gl/mX9DMQ
After: http://goo.gl/hPDKyt
Change-Id: Id9913024a46b0237dd2a1a9b0959eaa84aff379b
Merge "Move lockscreen buttons options to one place" into cm-11.0
Merge branch 'cm-11.0' into martincz