Telephony: Return 'null' when SubscriberId and Line1Number are unavailable

Return 'null' instead of "" (empty string) when Subscriber Id and
Line1Number are unavailable. This confirms to the definition of the
public API.

Bug: 8284793
Change-Id: Ie6395623cf413d51f6e10316aded71e2eaf5592c
1 file changed
tree: c0ec008e285dc5ab03db4fbcc861e553218272f8
  1. mockril/
  2. src/
  3. tests/
  4. Android.mk
  5. CleanSpec.mk