Telephony: Make resetting radio on a radio technology change optional

When there is a radio technology change in a multimode modem, resetting
the radio is not necessary always. Reset radio only when a property is
set. Notify applications that data connection is lost and ignore
notifications coming on the old radio technology.

Minor optimizations and bug fixes in CdmaDataConnectionTracker.
- Stop netstat polling when data connection is not active
- check all the elements of the data call list array to figure out if the
data connection is active.

Change-Id: I36785a9d1bf8ee135b574b61e9ba371faa04ffc7