Update TelecommManager per API requirements. (2/3)

+ Add constants GATEWAY_PROVIDER_PACKAGE and GATEWAY_ORIGINAL_ADDRESS
- Remove those corresponding constants from private packages
+ Modify clearAccounts() so it no longer takes an argument.

Bug: 17329632
Change-Id: I8b5f945f40dcab9e422ec2c69034a8e0c3249d0d