Settings: Use solid actionbar

When the action bar is visible, use the solid holo dark theme used
 by the rest of the Settings app

Change-Id: I41deeaa1988d59e121e6e81bcf3f42c570341f0b
Merge "Settings: Use solid actionbar" into cm-11.0
Merge pull request #20 from CyanogenMod/cm-11.0

Cm 11.0