Bug 909688 - Emulator: do not auto attach data registration. r=vicamo

Do not auto attach data registration when activating data call,
instead return error if data registration is unregistered when
activating/deactivating data call.
Merge pull request #48 from jessi3py/bug-909688

Bug 909688 - Emulator: do not auto attach data registration. r=vicamo
Merge remote-tracking branch 'b2g/master' into b2g-jellybean