Revert "apns: Add type default for Sprint."

This mask a real problem on devices on legacy cdma because we didn't
a stubbed apn for devices that don't use apn to connect to data.

this patch fixes it: http://review.cyanogenmod.org/#/c/62148/

this also problem with sprint 3g APN and lte apn numerics is the same
causing the apn stick together. one of those apn will always stick
persistently unless we force a manual disconnect or by selecting an apn
number from the list and that the 3g apn is due to the effect that it has
 no way determining on which apn is used in sprint. they do it by the
numeric, which is why most lte numerics apn is separate from 3g numeric.

We had a large debate on this issue once before, this is the same bug:

http://review.cyanogenmod.org/#/c/51425/

This reverts commit 5de6ec579e2dbe619eac1dac3152e9a863ba26ba.

Change-Id: Ia5c8310af0dce1805ae400d9f78c87c94cdc3cc2