Added global retry support

The retry timer suggested by the network will persist
accross network requests. Also changed the retry timer
to a 64-bit value to be consistent with types used in
Android time APIs.

(clean cherry-pick)

Test: FrameworksTelephonytests
Fix: 159672248
Merged-In: I763afdf34378512c60c0838830cb84875b1c66f0
Change-Id: I763afdf34378512c60c0838830cb84875b1c66f0