TeleService: fix event settings NPE

Has a bug in this commit when open Subscription settings:
Event settings already in Subscription settings - GSM call settings

http://review.cyanogenmod.org/#/c/74451/

PS2: This setting is added for non-world GSM phones only.
     Move this logic into the block that only gets executed for this case.
PS3: * Fix Event Notificatons for World Phone use case.
     * Don't call remove optional twice for msim.

Change-Id: I33fa9238b5a1715ce8a045a6d0b80bc66f9387e2

Conflicts:
	src/com/android/phone/CallFeaturesSetting.java
	src/com/android/phone/MSimCallFeaturesSubSetting.java
import com.android.phone.PhoneUtils.PhoneSettings;
Line

Change-Id: Ia1e40ca42b80fa17c9f87d980cd8d6e65f1a8d03