apns-conf-cdma: Remove Sprint CDMA MMS apn, conflicts with LTE/eHRPD …
…service

The old Sprint CDMA MMS apn uses the same MCC/MNC pair (310120) and apn
type ("default") as Sprint's LTE/eHRPD service.  Thus, Sprint LTE devices
attempt to connect to LTE/eHRPD services using the old CDMA MMS apn first,
which usually fails, and thus delays service establishment.

However, occasionally service "successfully" connects with the CDMA MMS
apn, for unknown reasons, at which point that apn is set as the preferred
apn for LTE connections.  Thus, any subsequent LTE/eHRPD connection attempt
fails due to use of the wrong apn.

By removing the old CDMA MMS apn, LTE/eHRPD connections will use the
appropriate apns.  Furthermore
com.android.mms.transaction.TransactionSettings::TransactionSettings does
not query the bearer field when looking for valid MMS apns, so the
LTE/eHRPD will continue to work on non-LTE Sprint devices.

Note that with this change, the MMS apn now specifies an mmsproxy.
cm: apns-conf.xml: (eHRPD/LTE handoff) Change pdp type for default APNs

This is to address hang-ups in eHRPD-LTE hand-offs as witnessed on d2spr.

Log of problem:

[GsmDC-6] Connecting to carrier: 'APN2 EHRPD internet' APN: 'n.ispsn' proxy: 'null' port: 'null'
[0319]> SETUP_DATA_CALL 15 0 n.ispsn null null 0 IPV4V6
....
qmi_ril(0/281): [event] qcril_data_event_hdlr: Dual-IP Partial Retry: Failure
qcril_data_event_hdlr: Dual-IP Partial Retry: Sending setup data call failure code

On stock rom:

[GsmDC-50] Connecting to carrier: 'APN2 EHRPD internet' APN: 'n.ispsn' proxy: '' port: '
[GsmDC-50] Allow IPv6 type request: false
[9240]> SETUP_DATA_CALL 15 0 n.ispsn 0 IP

Note, PDP type on stock rom/APN is not Dual-IP. Without information on how
"Allow IPv6 type request" is tested, for now force the PDP change via apns-conf.xml

Change-Id: Ic1cf9104fdd2dd579785f4b6f92b99a63cd74678