Always set NetworkInfo objects to available.

For all networks, NetworkInfo.isAvailble has basically always
been true for all connected networks. The new NetworkAgent API
sets it to false, and this causes application breakage. Always
set it to true.

Bug: 148126438
Test: builds, boots, searching in maps works again
Change-Id: Ia9876b0ce7f02120bd05cab526346cad22cf62b3
Merged-In: Ia9876b0ce7f02120bd05cab526346cad22cf62b3
(clean cherry-pick from internal branch)