Move pyglib.flags users from CamelCase/legacy to PEP8(snake_case)/new methods/functions.
Move pyglib.flags users from CamelCase/legacy to PEP8(snake_case)/new methods/functions.

CamelCase methods/functions will go away soon, as we are preparing the libraries for opensource as part of ABSL.

See LSC doc: http://go/absl-pep8-lsc

Tested:
    TAP --sample for global presubmit queue
    http://test/OCL:161709539:BASE:161696102:1499897365891:ca40d8c1

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=161842389

rarcotvmw/capirca,google/capirca,rarcotvmw/capirca,google/capirca,google/capirca,google/capirca,rarcotvmw/capirca