Migrating XTRA from gpsonextra.net to cloud based izatcloud.net

*Added logic to remove xtra1.gpsonextra.net from URLs
received from modem
*Added logic to override modem URLs with those configured
in gps.conf
*Replaced all instances of xtra{1,2,3}.gpsonextra.net domain URLs
in gps.conf with xtrapath{1,2,3}.izatcloud.net URLs.
*Replaced all commented instances of xtra.bin in gps.conf with xtra2.bin.

CRs-fixed: 643816

Change-Id: I803b26bce22f06910dcaa1ee057902b9381667bf