Use download.cyanogenmod.org instead of get.cm

The get.cm domain is cool, but to keep things consistent, we should
always point to download.cyanogenmod.org.  get.cm will soon be
redirecting to download.cyanogenmod.org.  Right now both of them work.

Change-Id: Icab87bc2e3b27d243e096d9246226c53f5669c7d
CMUpdater: DA translation

Port from cm-10.1

Change-Id: I6576831c47dd573081531dbb8e4c37cbf392fa38
update JSON URL

Change-Id: Id60ac9b68a3d91196ceb765a7adffae47bfbf282