Settings: standardize capitalization for Notification drawer

Change "Notification Drawer" to "Notification drawer", to conform
to the styling of all other entries.

Change-Id: I2ca125018226c8ec46d07a05a69ea063332008de
Merge "Settings: standardize capitalization for Notification drawer" into android-4.4
Merge branch 'android-4.4' of https://github.com/omnirom/android_packages_apps_Settings into android-4.4

Conflicts:
	res/values/custom_strings.xml