Correctly match SIP addresses.

When grouping items in the call log, we were using the function to
compare phone numbers. However, this strips all non-numeric characters,
which means that all SIP addresses without a number in them will match.

Instead, SIP addresses are defined to match only if they are identical.

Bug: 5483719
Bug: 5390325
Change-Id: Ic6f1d55ccbd433cc6062ca803fcfd88ae4f68a8a